Mailroom Technology, Inc.
230 Long Hill Cross Road
Shelton, CT 06484
Mailroom Technology, Inc.
FIPS 140-1
Cryptographic Module Security Policies
for the
Mailroom Technology, Inc.
Production Postal Security Device
SAFE CV 411, SAFE CV 412, SAFE CV 413
Note:
This document contains three Security Policy documents, one policy for each device.
When viewing the electronic version of this Security Policy and using Acrobat page
numbering, you will find the following:
The SAFE CV 411 SP is on pages 2-31 of 91 ref. SAFE CV 411
The SAFE CV 412 SP is on pages 32-61 of 91 which is page 1 of the
SAFE CV 412 SP Section. ref. SAFE CV 412
The SAFE CV 413 SP is on pages 62-91 of 91 which is page 1 of the
SAFE CV 413 SP Section. ref. SAFE CV 413
Mailroom Technology, Inc.
230 Long Hill Cross Road
Shelton, CT 06484
Mailroom Technology, Inc.
FIPS 140-1
Cryptographic Module Security Policy
for the
Mailroom Technology, Inc.
Production Postal Security Device
SAFE CV 411
Date: 20 March 2007
Version: 383SYS002D ver.6.6
File: PSD Security Policy 66.doc
Production PSD 383SYS002D
Approvals SAFE CV 411
Page ii
Approvals
Organization Responsibility Date
Engineering Name: George Brookner
Signature:
March 20 2007
Project Management Name: Don Eager
Signature:
March 20 2007
Engineering Name: Mark Ferraro
Signature:
March 20 2007
Name:
Signature:
Production PSD 383SYS002D
Change History SAFE CV 411
Page iii
Change History
Version By Changes
0.1 L. Frey First Edition
0.2 L. Frey The open questions have been transferred to a new document dedicated to that.
1.0 L. Frey First distributed version.
1.1 L. Frey Revision based on the answers to open questions (s. [s3lab3], [ASC3]) and new revision
1.3 of the SBB Specification.
1.2/1.3/1.4 Internal Review
2.0 L. Frey Release S3
lab, distributed to Ascom Hasler
2.1 L. Frey Internal Review: major modifications are:
• Use of input from
1) “Software Requirements Specification Postal Security Device”
2) “IBIP Interim Submission Concept of Operations”
3) “PSD Baseline Requirements & Architecture”
• Slight restructuring of the document using an example certificate (DS 1954
Cryptographic iButton) as background to make the security policy more “marketing
oriented” and “management readable”
• New section 4 to describe key management issues more coherent.
• No editor’s notes in the document any more. A separate document (“Underlying
assumptions” provided by S3
lab) summarizes any assumptions or open questions.
• The role/object/services concept is made more taut in order to emphasize more plain
what is the essence of the security policy, i.e. less objects and services and more
generalized items.
2.2 Internal Review
3.0 L. Frey Release S3
lab, distributed to Ascom Hasler
3.1/3.2 L. Frey Reviews, adjustment to key management concept release 0.9/DRAFT, Release to Meeting
in Shelton 10.3.99-12.3.99
4.0/4.1 L. Frey Changes due to the results of the meeting 11.3.99 in Shelton.
5.0 L. Frey Major revisions, reflecting the important changes of the USPS IBIP specifications and the
resulting modifications of the ASCOM key management system.
6.0 G. Brookner Major revision. Updated to reflect Remote Control capability of the production PSD in the
field as well as the certificate hierarchy.
Updated to reflect the Diffie-Hellman authenticated KMS session.
6.2 L. Frey Updated to include new worldwide key hierarchy structure and storage of certificates in
PSDs.
6.3 G. Brookner
M Ferraro
Clarified key zeroization, removed confidential footer, misc. spelling errors.
Updated in response to Cygnacom’s comments (07.July.2001).
6.4 R. Saunders
G. Brookner
Sections 1.1 para 4; 2.4 initialization, authorization, operation; 3.4 para 2; and 4 updated
in compliance with NIST recommendations.
Name changes from Ascom Hasler Mailing Systems to Hasler, Inc. [6/21/02].
Production PSD 383SYS002D
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6.5 M.Ferraro
G. Brookner
Modified the PSD to produce USPS IBI-Lite Indicia
Added the Mapping of “SAFE CV” to marketing names
Name changes from Hasler Mailing Systems to Mailroom Technology, Inc. [2003].
All references to Ascom and Hasler map to Mailroom Technology, Inc
6.6 M.Ferraro
‘Modified the PSD, added 3 bytes of indicia information to be encrypted and reduced the
size of the encrypted data result to 3 bytes.’
Production PSD 383SYS002D
Table of Contents SAFE CV 411
Page v
Table of Contents
1 INTRODUCTION 1
1.1 Purpose 1
1.2 Terminology 1
2 PRODUCT IDENTIFICATION 2
3 PRODUCT DESCRIPTION 2
3.1 The Postal Security Device (PSD) 2
3.2 Purpose of the Postal Security Device (PSD) 3
3.3 Use of the Postal Security Device (PSD) 3
3.4 Life Cycle/Phases 4
3.5 Security Objectives of the Postal Security Device (PSD) 6
3.6 Physical Security 7
4 ROLES, SERVICES AND ACCESS CONTROL 7
4.1 Roles and Authentication 7
4.1.1 ASCOM Root CA 8
4.1.2 ASCOM Regional CA 8
4.1.2.1 Regional KMS 8
4.1.2.2 ASCOM Factory Region 8
4.1.3 ASCOM Manufacturing 8
4.1.4 ASCOM Remote Control 9
4.1.5 TMS 9
4.1.6 Customer 9
4.2 Protected Assets 10
4.2.1 PSD configuration 10
4.2.2 Indicia application configuration 10
4.2.3 Postal Funds 10
4.2.4 Customer Attributes 11
4.2.5 Statistics and Records 11
4.2.6 Cryptographic Keying Material 11
4.3 Services and Access Control Policy 11
4.3.1 General Device Initialization 13
4.3.2 Customer Specific Initialization 13
4.3.3 Funds Download 13
4.3.4 Indicia Generation 14
4.3.5 Log Extraction 14
4.3.6 Information 14
4.3.7 Management of Cryptographic Services 14
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Table of Contents SAFE CV 411
Page vi
4.3.8 Customer Authentication 15
4.4 Enabling/Disabling the Postal Security Device (PSD) 16
5 KEY MANAGEMENT 16
5.1 ASCOM Root CA certificate 18
5.2 Ephemeral Diffie-Hellman Key Pair 18
5.3 ASCOM (Factory Region) Regional CA certificate 18
5.4 ASCOM Manufacturing certificate 18
5.5 ASCOM Regional CA certificate 19
5.5.1 Region Codes 19
5.6 PSD Authentication Key Pair 19
5.7 ASCOM Remote Control certificate 20
5.8 Indicia Key Pair 20
5.9 TMS Keys 21
5.10 User PIN Keys 21
5.11 Random Number Generation 21
6 IBI-LITE INDICIA 21
7 ANNEXES 22
7.1 References 22
7.2 Acronyms 22
3.2 Purpose of the Postal Security Device (PSD) 3
3.3 Use of the Postal Security Device (PSD) 3
3.4 Life Cycle/Phases 4
3.5 Security Objectives of the Postal Security Device (PSD) 6
3.6 Physical Security 7
7 ANNEXES 22
7.1 References 22
7.2 Acronyms 22
Production PSD 383SYS002D
Figures SAFE CV 411
Page vii
Figures
Figure 3-1: Architecture of the SAFE CV 411..................................................................................... 3
Figure 3-2: Principle Life Cycle of the PSD ........................................................................................ 5
Figure 3: Neopost Organization ........................................................................................................... 1
Tables
Table 1 SAFE CV to MATS ID Mapping............................................................................................ 2
Table 2: Protected Objects ................................................................................................................. 10
Table 3: PSD Services........................................................................................................................ 12
Table 4: Cryptographic elements stored in the PSD .......................................................................... 17
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Introduction SAFE CV 411
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1 Introduction
1.1 Purpose
This is a Cryptographic Module Security Policy for the MAILROOM TECHNOLOGY
INC. Postal Security Device. This policy was prepared for the purpose of a FIPS 140-1
[FIPS94] certification of the Postal Security Device. FIPS 140-1 gives U.S. Government
requirements for cryptographic modules, and defines the Security Policy as:
“A precise specification of the security rules under which the cryptographic module must
operate, including rules derived from the security requirements of this standard, and the
additional security rules imposed by the manufacturer.”
The security of the Postal Security Device meets FIPS 140-1 level 3 requirements with respect
to physical security (as specified in section 4.5 in FIPS 140-1) and level 3 in all other aspects.
Per USPS requirements, the module meets FIPS 140-1 Level 4, Environmental Failure Testing
(EFT).
This security policy describes how this is done and how the Postal Security Device is to be
used and operated in a secure fashion. The module operates only in a FIPS compliant mode
and does not support a non-FIPS mode.
1.2 Terminology
Ascom’s Secure Funds Authenticated Funds Engine (SAFE), model SAFE CV 401/411, will
be denoted as “PSD” throughout this document..
The Term “indicia” is used throughout this document to denote the digital Information Based
Indicia as specified by the US Postal Service. All services and functions of the PSD provided
with respect to indicia (like indicia generation, funds management and related diagnostics) are
called collectively “indicia application”.
The acronym “TMS” (for “TeleMeter Setting System”) is used to denote a certain PSD
external entity entitled to perform privileged operations on the indicia application (like
downloading of funds).
The acronym “KMS” (for “Key Management System”) is used to denote a certain PSD
external entity entitled to perform privileged operations related to the management of
cryptographic material.
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2 Product Identification
The device will be identified as SAFE CV 411. This identification will be extended across
various marketing models.
The following table maps the “SAFE CV” Software version number to USPS MATS ID’s and
Neopost/Hasler Marketing Names.
SAFE CV 411 Software
Version
Marketing Name
TLE 401 V3.3.2
Hallmark TLE 481 V3.3.2
Hasler
Symphony
140 V3.4.0
Neopost
Symphony
N360 V3.4.0
Table 1 SAFE CV to MATS ID Mapping
3 Product Description
3.1 The Postal Security Device (PSD)
The PSD device is a multiple chip embedded module designed as a single electronic circuit
board with interfaces to a serial external port and a power supply. The board is enclosed with a
tamper detecting “continuity” mesh and sealed in a hard opaque heat transferring potting
compound. Together these elements both conceal the electronic circuitry and provide for
tamper detection and response. Further, tampering cannot occur without significant visual
damage to the potting material, board or board components. No physical access to the PSD
(e.g. battery replacement) is possible.
The main processor executes a static application. The primary objective of this application is
to protect the Postal funds and to apply respective access rules. Various memory components
and supporting processors (like cryptographic processors) are used.
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The general architecture of the PSD is depicted in the following diagram. The difference
between the SAFE CV 401 and SAFE CV 411 is the external enclosure form factor.
Figure 3-1: Architecture of the SAFE CV 411
3.2 Purpose of the Postal Security Device (PSD)
The PSD supports the creation of authorized indicia, which shows evidence of postage
payment. The indicia consists of a two-dimensional bar code and certain human readable
information such as a Device ID Number, date of mailing, amount of postage, mailer’s
location (city & state or ZIP Code) and rate category.
The PSD provides for the accurate accounting of postal funds. It holds the funds needed for
the postage and produces on request of the USPS customer digitally signed data sets, each
representing indicia. It is designed to adhere to applicable USPS regulations [USPS00].
3.3 Use of the Postal Security Device (PSD)
The PSD is integrated in or connected to some host system under the custody of the customer
(like a PC or within a metering/mailing device). The customer may access the PSD and
instruct it to generate indicia on his behalf by using some application software running on the
host system. The indicia will be used by the host system to produce the actual printed indicia
on mail pieces with suitable printers.
Crypto Boundary
Power
protection
Circuitry
Opto Isolator
Flash Memory Chip
Select
Unit
Bus
Interface
Unit
PIO Unit
CPU
Core
Serial
Port 1
Serial
Port 0
Clock/Pwr
Mgmt Unit
Interrupt
Control
Unit
Timer
Control
Unit
Main Processor
I/O
Connector
Misc.
Logic
Internal
Comm
MUX
True Random No. Generator
Crypto Coprocessor
Security Sensors
Power on/off Reset
Serial Interface
CPU Core
Program Memory
EEPROM
Timers
Crypto Processor
Power
Supervisor
Tamper
Detection/
Response
Battery
Flash
Memory
Real-Time
Clock
SRAM
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The host system also provides a communication link (e.g. using a modem) to certain external
entities with administrative or application related privileged responsibilities. These entities are
part of the background infrastructure provided by ASCOM.
The ASCOM Telemeter Setting ® (TMS ®) data center is responsible for the (remote)
download of new postal funds, the upload of audit information and other application
management related operations.
ASCOM Regional CA and ASCOM Remote Control acting as administrators may access the
PSD in the field (remotely) and are allowed to manage cryptographic elements.
ASCOM may perform diagnostic operations with a PSD when it is returned from the customer
to ASCOM, thereafter leading to the PSD being re-manufactured or scrapped.
The communication between the PSD and any of those privileged entities introduced before
are protected by cryptographic means. The PSD itself has a secure containment.
The entity “KMS” or more precisely its logical constituents ASCOM Regional CA, ASCOM
Remote Control and TMS may access the PSD in the field (remotely) and are allowed to
provide such operations as changing cryptographic keys, disabling PSDs, providing secure
session operations for the exchange of protected data with the PSD. These processes provide
authentication, integrity protection and encryption means for said data interchanges.
3.4 Life Cycle/Phases
The PSD is manufactured and initialized at ASCOM facilities and then delivered to customers
for operational use in the field. The PSD returns for decommissioning or for failures reported
by the customer to ASCOM. As necessary, ASCOM may recover any postal funds stored in
the PSD and arrange for the crediting of the respective amount to the customer.
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Product Description SAFE CV 411
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Manufacturing
Manufacturing
Initialization
Initialization
Authorization
Authorization
Operation
Operation
Return
Return
ASCOM
Field
Re-Keying
Re-Authorization
Figure 3-2: Principle Life Cycle of the PSD
Manufacturing of the PSD is done in ASCOM facilities and consists of basic preparations of
the PSD for its later use. This includes primarily the identification of the PCB and the
initialization of the PCB’s internal clock. Then, the enclosure is put on the PCB making the
PSD ready for initialization.
Initialization makes the PSD ready for shipment into the field. This process, which also takes
place on ASCOM premises, basically includes the following steps:
1. Loading and initialization of the actual IBIP application software and related data.
2. Initialization of PSD Authentication Keys used to establish a secure communication later
on between a PSD in the field and the ASCOM infrastructure.
3. Initialization of the PIN keys used for secure transmission of the PIN for Customer
authentication to the PSD.
4. Loading of cryptographic certificates used to authenticate administrative roles.
From now on and until returned to ASCOM, the PSD is regarded as being in a potential hostile
environment (the “field”). The PSD protects all assets including the postal funds,
cryptographic material and available services according to the rules presented herein. Roles
and Services are described subsequently.
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An authorized dealer may ship the PSD to the customer as an alternative to direct shipment
from ASCOM.
In the Authorization phase, a given PSD is assigned to a specific customer whose attributes
are put into the PSD. Related (external) registration activities take place to make the PSD and
the relationship to the given customer known to the background infrastructure (ASCOM and
TMS). The PSD is now ready to be used by the customer from a technical point of view, but
has still no postal funds in it.
In the Operation phase, the first step is to load postal funds into the PSD, which is done by
TMS. The customer may produce digital Information Based Indicia now, using the available
postal funds at his discretion. During the operational use of the PSD, the TMS will
communicate with the PSD from time to time in order to download new postal funds and to
audit the device.
A PSD in the field may run through a new, partial Authorization (referred to as Re-
Authorization), remotely controlled by ASCOM, if arises (e.g. due to changed customer data
as address).
A PSD in the field may undergo Re-Keying, remotely controlled by ASCOM Remote
Control. During this phase all or part of the cryptographic keying material (private keys,
public key certificates) stored by the PSD may be replaced by new one.
The PSD may be returned for regular de-commissioning or other reasons (e.g. technical
failure, suspected tampering) to ASCOM. ASCOM may access the PSD for diagnostic
purpose and in order to recover the customer’s postal funds stored in the PSD. However, the
PSD prevents any access to secret or private keys in that procedure. The SAFE’s internal
hardware and connections are not replaceable. Any defect is unserviceable. Depending upon
the operational status of the PSD, it may either be destroyed or sent through the manufacturing
and initialization process.
3.5 Security Objectives of the Postal Security Device (PSD)
The PSD is primarily a secure device holding an amount of postal funds, which the USPS
customer currently possessing the PSD may use to produce digital Information Based Indicia.
The following assertions apply to the PSD:
A1 The major asset contained in the PSD is the current amount of postal funds stored
in it.
A2 The customer may request the PSD to create digital Information Based Indicia.
A3 The PSD enforces the proper reduction of the available amount of postal funds as
part of producing a digital Information Based Indicia.
A4 The downloading of new postal funds may be initiated by the customer but not
influenced otherwise. The downloading is done by TMS.
A5 The customer may recognize the status of the postal funds and the PSD in general.
A6 Initial cryptographic data (e.g. keys, certificates and relevant cryptographic
parameters) required for authentication is initialized on ASCOM premises in a
secure environment controlled by ASCOM Manufacturing.
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A7 Cryptographic keys or certificates may be changed in the field. This is an
administrative responsibility of ASCOM KMS entities (e.g. ASCOM Regional CA
and/or ASCOM Remote Control).
A8 Secret and private keys needed to enforce these security objectives never leave the
PSD.
These security objectives are fulfilled by the PSD by authenticating the respective roles and
using the caller’s role as reference for controlling the use of services and access to assets. This
is done each time a service is requested from the PSD.
3.6 Physical Security
The physical security of the PSD will be governed by the physical security requirements of
FIPS PUB 140-1 Level 3. The security boundary of the PSD is encapsulated within a plastic
enclosure filled with hard opaque potting material. There is no access to the internal
components without showing tamper evidence. The potting material offers a high degree of
tamper resistance, causing physical destruction to components if removal is attempted. The
PSD also utilizes tamper detection countermeasures that respond to tampering by zeroing
cryptographic keys and disabling the PSD from further use.
4 Roles, Services and Access Control
4.1 Roles and Authentication
Certain roles are identified by the PSD for the purpose of allowing access to services:
• ASCOM Root CA,
• ASCOM Regional CA,
• ASCOM Manufacturing,
• ASCOM Remote Control,
• TMS,
• Customer.
ASCOM Root CA is the highest level of authority in the certificate hierarchy and is the
identity that assumes the Crypto Officer role that is enacted to issue all ASCOM Regional CA
certificates used by the PSD to authenticate regional KMS entities. ASCOM Root CA also
signs PSD-resident applications.
Both entities, ASCOM Regional CA and ASCOM Remote Control, may access the PSD in the
field for the purpose of the management of cryptographic elements in the PSD and thus
represent the “Crypto Officer” during the operational phase of the PSD.
ASCOM Manufacturing has the responsibility for initializing the PSD with cryptographic
keying material during the manufacturing and initialization phase. ASCOM Manufacturing
thus represents the “Crypto Officer” on ASCOM premises. ASCOM Manufacturing may
never access a PSD in the field.
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TMS and Customer represent the “User” of the PSD, specifically the user of the indicia
application. Some services with an informative purpose only are provided by the PSD in the
field and may be requested by an entity at any time (e.g. Licensing Zipcode, Account Number,
Customer Type, Daylight Savings, Time Zone (Local Time), PSD Owner). The external entity
calling these services is not expected to explicitly represent a certain role to the PSD.
4.1.1 ASCOM Root CA
ASCOM Root CA represents the highest cryptographic authority of the key management
system run by ASCOM for the indicia application and as such issues all certificates of the next
lower level of the KMS, i.e. the ASCOM Regional CA certificates.
The self-signed certificate of ASCOM Root CA is stored in each PSD.
4.1.2 ASCOM Regional CA
ASCOM Regional CA represents the highest cryptographic authority of a KMS for a single
country or region of a country.
It acts as the Certification Authority for its population of PSDs and the other regional KMS
entities.
ASCOM Hasler maintains control over the Region Change process. No Regional KMS can
take over control of PSDs that belong to a different Regional KMS. All PSDs that are shipped
from ASCOM Hasler Manufacturing are "generic" and can be assigned to any region. But any
PSD assigned to a particular region can change its region only back to ASCOM Hasler
Manufacturing.
4.1.2.1 Regional KMS
A regional KMS supports all PSDs within a single country or defined region of that country
(excluding the ASCOM Factory Region). As the highest local cryptographic authority, the
ASCOM Regional CA issues all Remote Control certificates and issues all PSD
Authentication certificates in that particular region.
4.1.2.2 ASCOM Factory Region
The Factory Region is a dedicated regional KMS introduced to provide the cryptographic
support for the manufacturing and initialization of new PSDs and the return of PSDs from the
field. The structure of its KMS is identical to the one of any other regional KMS. Thus, the
Factory Region has its own ASCOM Regional CA that signs all ASCOM Manufacturing
certificates. It also issues the PSD Authentication certificate for a PSD under manufacture.
4.1.3 ASCOM Manufacturing
ASCOM Manufacturing represents the manufacturer of the PSD and is responsible for all
activities applied to the PSD within the premises of ASCOM (manufacturing, initialization
and return procedures). The Manufacturing entity exists only in the Factory Region, and
authenticates the KMS to a PSD under manufacture, or after its return from a customer.
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4.1.4 ASCOM Remote Control
ASCOM Remote Control directly or on behalf of ASCOM Regional CA, is authorized and
responsible for accessing the PSD for various administrative purposes in the field. This
includes:
• initiating the generation of a new indicia key pair (re-keying),
• resetting the customer’s PIN,
• loading the customer specific data in the (Re)-Authorization phase,
• enabling or disabling the indicia application and
• extracting indicia application related statistic and logfiles 1
.
Each message from ASCOM Remote Control is authenticated by the PSD. In particular, all
messages exchanged for the purpose of replacing an indicia key pair are protected by
cryptographic means. While digital signatures provide entity authentication and data integrity,
data confidentiality is protected by symmetric encryption.
4.1.5 TMS
TMS is responsible for controlling the postal funds in the PSD. TMS may only download new
postal funds and activate or deactivate the indicia creation service. This is supported by an
automatic watchdog mechanism in the PSD enforcing a periodical audit of the PSD’s funds
related services by TMS.
Cryptographic means are used as part of a specific protocol (TMS-II protocol) to authenticate
the respective sender of messages (TMS or the PSD) and to protect the data integrity and (if
needed) confidentiality of the message exchanges.
The security of the TMS-II protocol is based on the following features:
• prevention of message replaying by the use of Triple DES session keys and time variant
parameters,
• mutual authentication of both the PSD and TMS,
• transaction data integrity using a DESMAC for each message,
• selective confidentiality for parts of the message as appropriate.
4.1.6 Customer
The Customer is allowed to use the PSD to produce indicia, which consumes the available
postal funds in the PSD. In order to do so he has to perform a “login” into the PSD by
presenting a PIN, which identifies him/her (for details see section 4.3.8).
1
This may take place in the field, but will also be done as the first step in the Return phase.
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4.2 Protected Assets
The major asset held in the PSD is the currently available amount of postal funds. Several
more objects are identified in order to provide a more detailed picture of the PSD’s access
control policy.
Table 2: Protected Objects
PSD configuration
Indicia application configuration
Postal funds
Customer attributes
PIN
Statistics and records
Cryptographic keying material
4.2.1 PSD configuration
Hardware and software of the PSD are configured in the manufacturing and initialization
phase on ASCOM’s premises. The PSD configuration is the hardware and software along with
more basic operational parameters and data objects of the PSD in the field 2
. Operational
parameters and data objects include for example date and time (along with related parameters)
and any data identifying the hardware and software (e.g. meter serial number).
Any modification of the hardware/software of a PSD having been in the field requires the
return of the device to ASCOM facilities beforehand, following proper return procedures (see
section 3.4).
4.2.2 Indicia application configuration
Various parameters, some of them being defined specifically for a customer, are used to
control the indicia application. These parameters include various limits applied when
performing indicia related transactions.
4.2.3 Postal Funds
The most important data item managed by the indicia application is the amount of postal
funds, which is available for consumption via indicia generation. Specific security
requirements imposed by USPS apply to the postal funds related management functions and
access methods. The postal funds are decreased every time an indicium is generated and
increased by a TMS originated download of new funds.
2
It is this configuration, which is primarily subject to security policy considerations in this document.
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4.2.4 Customer Attributes
Various attributes are used to identify and describe the customer. These customer attributes
include a license ID, a corresponding ZIP code and the Customer’s accounting number used
by TMS for accounting purposes.
4.2.5 Statistics and Records
The PSD maintains various statistics and records about the use of services related to the postal
funds and indicia generation. These statistics and records include recent transactions and
various events as reaching application related limits, funds transfers from TMS, errors,
warnings and the modification of parameters related to those services.
4.2.6 Cryptographic Keying Material
The indicia are primarily secured by a digital signature generated with a dedicated private key
stored in the PSD. Other cryptographic keys are used to authenticate the entities ASCOM CA,
ASCOM Regional CA, ASCOM Remote Control and ASCOM Manufacturing. Domain
parameters used by any cryptographic mechanisms are also regarded as being a part of the
cryptographic keying material3
.
Keys and certificates stored in a PSD consist of:
• ASCOM Root CA certificate,
• ASCOM (Factory Region) Regional CA certificate (temporarily),
• ASCOM Regional CA certificate,
• ASCOM Manufacturing certificate (temporarily),
• ASCOM Remote Control certificate (temporarily),
• PSD Authentication certificate and the corresponding private key,
• Indicia certificate and private key,
• User PIN Keys,
• TMS keys,
• Ephemeral Diffie-Hellman keys (temporarily).
4.3 Services and Access Control Policy
The PSD provides various services to external entities as presented in Table 3 and described
hereafter.
Note: This security policy focuses on the PSDs in the field (see sect. 3.4). References to
manufacturing related phases (Manufacturing and Initialization) as well as to the Return phase
are made here only to provide the reader with a complete picture of the overall life cycle.
3
The meaning and use of the cryptographic keying material is described in more detail in Section 4.3.7 and
Section 5.
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Table 3: PSD Services
Service Roles Access allowed for Life cycle
phase
C.O. User
General Device
Initialization
X ASCOM Manufacturing Initialization
Customer
Specific
Initialization
X ASCOM Remote Control Authorization
Funds
Download
X TMS Operation
Indicia
Generation
X Customer Operation
Generate
Indicia Key Pair
X ASCOM Remote Control
(ASCOM Manufacturing)
Authorization
(Return)
Get Indicia
Public Key
X ASCOM Remote Control
(ASCOM Manufacturing)
Authorization
(Return)
Generate
Authentication
Key Pair
X ASCOM Manufacturing Initialization
Get
Authentication
Public Key
X ASCOM Manufacturing Initialization
Generate Diffie-
Hellman Key
Exchange for
TDES Session
Key Creation
X X ASCOM Manufacturing
ASCOM Remote Control
TMS
Initialization
Authorization
Operation
Generate PIN
Keys
X X ASCOM Manufacturing
Customer
Initialization
Operation
Generate TMS
Keys
X TMS Operation
Get Certificates X ASCOM Manufacturing
ASCOM Remote Control
Initialization
Authorization
Log Extraction X ASCOM Remote Control
(ASCOM Manufacturing)
Operation
(Return)
Information X X All Operation
(Return)
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Management of
Cryptographic
Services
X ASCOM Remote Control
(ASCOM Manufacturing)
Operation
(Initialization/
Return)
Customer
Authentication
X X Customer (see section 4.3.8) and ASCOM
Remote Control
Operation
Enabling/Disabl
ing the PSD
X X TMS and
ASCOM Remote Control
Operation
4.3.1 General Device Initialization
ASCOM Manufacturing will initialize the PSD device when it leaves the Manufacturing
phase. This process will initialize the indicia application along with all its related data
completely as defined by ASCOM Manufacturing. The new application is loaded into the PSD
as part of the functions related to this service.
ASCOM Manufacturing, in the initialization phase of the PSD, uses certain special diagnostic
applications and other initialization applications in order to initialize various data objects and
finally to load the indicia application which provides the control for use of the PSD in the
field.
Data to be initialized includes the current date, time and attributes which identify and describe
the specific device.
4.3.2 Customer Specific Initialization
This service includes functions performed by ASCOM Remote Control in the field in order to
configure the PSD for the use with a specific customer.
This includes loading of attributes identifying and describing the specific customer. It also
includes the setting of values for parameters, which are specific for the customer and are
recognized by the indicia application in operation (e.g. limits for new funds).
4.3.3 Funds Download
TMS may access the PSD in the field through the KMS functional entity for downloading of
new funds. The communications with the PSD and the related exchange of TMS data is
accommodated via the cryptographically secured messaging mechanism specified in section
4.3.7.
TMS carries out the following operations as part of the funds downloading operation:
• receives a request for download of new funds and grants new funds after having performed
suitable checks and
• performs a check of the value of postal funds in the PSD allowing TMS to compare it with
available information for correctness (“device audit”);
• reads various values and parameters of the PSD configuration, the Indicia application
configuration and the customer attributes;
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• may modify the PSD’s date-and-time;
• releases the PSD for further use.
The PSD tracks the remaining amount of available funds and the total amount of funds used
for indicia creation4
.
A PSD internal Watchdog timer is used to automatically inhibit further indicia creations until
proper audit is done.
The TMS provides the accounting services necessary to support USPS funds management
requirements.
4.3.4 Indicia Generation
The Customer may generate indicia using the available funds [USPS00]. The creation of
indicia decreases the available amount of funds while it increases the overall sum of funds
used. Any other change of the funds is restricted to TMS.
A precondition for indicia generation is that the PSD indicia application function is not
disabled because of an overdue audit (see section 4.3.3).
4.3.5 Log Extraction
ASCOM Remote Control may extract Statistics and Records from PSDs in the field for
diagnostic purposes, while ASCOM Manufacturing may extract this data as part of the Return
procedures.
4.3.6 Information
The PSD provides service functions to access various information available in the PSD. This
information is generally not regarded as confidential. The respective service commands may
be accessed therefore without the need of a preceding authentication.
Information available includes:
• the current amount of postal funds;
• the value of various application relevant parameters (as applicable limits);
• various attributes identifying and describing the specific customer and the device;
• diagnostics and status information about the PSD device.
4.3.7 Management of Cryptographic Services
ASCOM Manufacturing and ASCOM Remote Control may query and set various elements of
the PSD’s cryptographic material (see section 4.2.6) within the context of the key management
concept described in section 5.
Available functions for ASCOM Manufacturing in the Initialization phase are:
4
These values are referred to conceptually as “descending register” and “ascending register”, see [USPS00].
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• initiate the generation of a PSD authentication key pair in a PSD and get the public key
component for certification;
• initiate the generation of the PIN keys used to decrypt the securely transmitted PIN
received for Customer authentication to the PSD,
• set and verify cryptographic parameters and certificates.
Available functions for ASCOM Remote Control in the field are:
• initiate the generation of a Indicia key pair in a PSD and get the public key component
from the PSD for certification;
• re-keying of a PSD (e.g. initiate the PSD internal generation of a new Indicia key pair);
• PSD log extraction.
The data exchanged for the purpose of the management of cryptographic services is secured
using an “authenticated Diffie-Hellman channel” with data integrity protection and symmetric
encryption.
The communications protocol used to establish the secure channel provides the following
security features:
• replay protection by using random numbers as time variant parameters;
• establishment of shared secret session keys between the two communicating entities by
Diffie-Hellman technique;
• mutual control of the shared secret keys;
• forward secrecy for the shared secret session keys (a compromised key does not put at risk
future session keys);
• authentication of the communicating parties by the use of digital signatures and
certificates;
• encryption and integrity protection through use of symmetric techniques;
• independent cryptographic keys for encryption and integrity protection.
4.3.8 Customer Authentication
The PSD is a single-user device that uses identity-based methods to authenticate its user. The
Customer is allowed to use the PSD to produce indicia that consumes the available postal
funds in the PSD. In order to do so, he has to perform a “login” into the PSD by presenting a
PIN to identify himself.
The Customer is authenticated using a PIN based mechanism. The PIN is set to a unique PSD
individual value in the Manufacturing phase. This value is made known to the customer using
a communication path different from the shipping of the PSD itself. The customer is
empowered to change the PIN when he uses the PSD the first time.
The PSD expects the customer identity PIN to be entered each time after powering up and
before using the customer role. The PSD also expects the PIN authentication procedure to be
performed again each time the synchronization at the serial interface between the PSD and the
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host system is lost. This event indicates to the PSD that it might have been moved to a
different host system.
PIN authentication must be performed, before any indicia application function (indicia
generation and TMS activities) is allowed by the PSD.
Whenever a specific consecutive number of authentication failures has occurred the PIN
authentication function is locked, which effectively prevents the access to the indicia
generation. ASCOM Remote Control may reset the PIN to its initial value.
At first power-up of an initialized PSD, the customer enters the PIN through a keypad on the
host/base. The host/base then encrypts the PIN and transfers it to the PSD. The Customer is
not forced to re-enter the PIN at each power-up since this is the only entity that accesses the
module through this interface, in the field.
The PIN is protected by encryption prior to transmission from the host/base to the PSD by
symmetric keys. This applies to both the regular entry of the current PIN and to a PIN change.
The PIN is never communicated in the clear.
The PIN keys are triple DES keys generated by the PSD and used for secure transmission of
the Customer PIN. This process is initially performed in the initialization phase.
4.4 Enabling/Disabling the Postal Security Device (PSD)
Based on several pre-defined security criteria (e.g. time, postal funds or piece count based
limits) operations of a PSD in the field may be enabled/disabled remotely by TMS and
ASCOM Remote Control, respectively, in case one or more of the criteria are met.
The battery-backed RAM contains all the security-critical data elements such as the
certificates and keys. When the electronic tamper response mechanism is activated, all the
security-critical data elements in RAM are destroyed (zeroed) thus making the PSD
inoperative.
5 Key Management
The following cryptographic elements are stored in a PSD:
• ASCOM Root CA certificate,
• ASCOM (Factory Region) Regional CA certificate (temporarily),
• ASCOM Regional CA certificate,
• ASCOM Manufacturing certificate (temporarily),
• ASCOM Remote Control certificate (temporarily),
• PSD Authentication certificate and the corresponding private key,
• Indicia certificate and private key,
• User PIN Keys,
• TMS keys,
• Ephemeral Diffie-Hellman keys (temporarily).
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Table 4: Cryptographic elements stored in the PSD
Cryptographic
element
Generation Initialization in
PSD
Usage by PSD Replacement in PSD
ASCOM Root CA
certificate
Generated by
ASCOM Root
CA
Manufacturing/
initialization phase
Verification of Regional
CA certificates.
Verification of signatures
on PSD application
binaries.
As part of re-keying
When Return application
is loaded
Ephemeral Diffie-
Hellman key pairs
Generated by
PSD
Initialization/Autho
rization/Operation
phase
(Temporarily)
Creation of session keys
for secure communication
with the KMS.
Whenever a secure
communication session is
created
ASCOM (Factory
Region) Regional
CA certificate
Issued by
ASCOM Root
CA
Manufacturing/
initialization phase
(Temporarily)
Verification of
Manufacturing Certs
(only Factory Region).
As part of Authorization
When Return application
is loaded
ASCOM
Manufacturing
certificate
Issued by
ASCOM
(Factory
Region)
Regional CA
Manufacturing/
initialization phase
(Temporarily)
Verification of ASCOM
Manufacturing and signed
data of message
exchanges with KMS.
As part of Authorization
When Return application
is loaded
ASCOM Regional
CA certificate
Issued by
ASCOM Root
CA
Authorization phase Verification of Remote
Control Certs.
As part of re-keying
When Return application
is loaded
PSD Authentication
key pair
Generated by
PSD
Initialization phase Private key signs data of
message exchanges with
regional KMS
As part of re-keying
When return application is
loaded
ASCOM Remote
Control certificate
Issued by
ASCOM
Regional CA
Authorization phase (Temporarily)
Verification of ASCOM
Remote Control and
signed data of message
exchanges with KMS.
As part of re-keying
Indicia key pair Generated by
PSD
Authorization phase Private key signs indicia
data
As part of re-keying
When Return application
is loaded
TMS keys Agreed by
PSD and TMS
Operation phase Provide mutual
authentication of TMS
and PSDs and protection
of data integrity and
confidentiality
As part of every postal
funds download operation
When Return application
is loaded
User PIN Keys Initially
Generated by
PSD
Operation phase Logon to PSD When user enters his/her
own PIN
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5.1 ASCOM Root CA certificate
The ASCOM Root CA certificate is loaded into each PSD during the Manufacturing/
Initialization phase.
The ASCOM Root CA certificate is self-signed. It contains a hash of the next public key and
the associated cryptographic domain parameters.
The security of a subsequent replacement of the ASCOM Root CA Certificate (whether
accomplished remotely, in the field, or as part of the return re-manufacturing process) is based
on the data origin authentication and integrity protection provided by the hash value (being
part of the signed data) stored in the previous version of the ASCOM Root CA certificate.
The ASCOM Root CA private key is applied to issue ASCOM Regional CA certificates and to
sign PSD application binaries.
The PSD uses the ASCOM Root CA certificate to verify subsequent ASCOM Regional CA
certificates and to check the signature on application binaries to be loaded.
The first time an application is run it is verified against this signature, then a CRC is
calculated/stored and all subsequent startups of the application verify this CRC.
5.2 Ephemeral Diffie-Hellman Key Pair
The Diffie-Hellman key pairs are initially created by the PSD during the Manufacturing/
Initialization phase. These keys are used to establish shared secrets for authenticated Diffie-
Hellman communication sessions with the KMS for which, data integrity and confidentiality
are protected, see section 4.3.7.
5.3 ASCOM (Factory Region) Regional CA certificate
The ASCOM (Factory Region) Regional CA certificate is loaded into each PSD during the
Manufacturing/Initialization phase.
The ASCOM (Factory Region) Regional CA certificate is issued by the ASCOM Root CA.
The ASCOM (Factory Region) Regional CA private key is used to issue the following
certificates:
• ASCOM Manufacturing certificates;
• PSD Authentication certificates.
The PSD uses the ASCOM (Factory Region) Regional CA certificate to verify the ASCOM
Manufacturing certificate and thus the corresponding role.
The ASCOM Regional CA certificate is only temporarily stored in the PSD and is replaced
during the Authorization phase by the ASCOM Regional CA certificate when the PSD is sent
to a destination in the field.
5.4 ASCOM Manufacturing certificate
The ASCOM Manufacturing certificate is loaded into each PSD during the Manufacturing/
Initialization phase.
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The ASCOM Manufacturing certificate is issued by the ASCOM (Factory Region) Regional
CA.
The ASCOM Manufacturing private key is used to sign messages sent by ASCOM
Manufacturing to the PSD. The PSD uses the ASCOM Manufacturing certificate to verify the
ASCOM Manufacturing role and any signed messages sent by the entity. The ASCOM
Manufacturing certificate is only temporarily stored in the PSD and is replaced during the
Authorization phase by the Remote Control certificate when the PSD is sent to a destination in
the field.
5.5 ASCOM Regional CA certificate
The ASCOM Regional CA certificate is loaded into each PSD during the Authorization
phase5
.
The ASCOM Regional CA certificate is issued by the ASCOM Root CA.
The ASCOM Regional CA private key is used to issue the following certificates:
• ASCOM Remote Control certificates (or ASCOM Manufacturing certificates for the
Factory Region);
• PSD Authentication certificates.
The PSD uses the ASCOM Regional CA certificate to verify ASCOM Remote Control
certificate and thus the corresponding role.
In the field, ASCOM Remote Control may initialize a replacement of the ASCOM Regional
CA certificate in a specific PSD as part of a re-keying operation. This operation is integrated
in an authenticated Diffie-Hellman communication session for which, in addition, data
integrity and confidentiality are protected, see section 4.3.7.
The ASCOM Regional CA certificate contains a Region Code that controls when a new
regional certificate can replace an existing regional certificate in a PSD.
5.5.1 Region Codes
A Region Change procedure is used to reconfigure a PSD when it moves from one region to
another.
Each ASCOM Regional CA certificate will contain two region codes, the "Active Region
Code" and the "Prior Region Code". These region codes act as constraints on the certificate
change process to provide the ability to configure a PSD to its regional certificate hierarchy,
reconfigure a returned PSD for ASCOM manufacturing, and not allow a regional KMS to
reconfigure a PSD for a different region, cf. section 4.1.2.
5.6 PSD Authentication Key Pair
The PSD Authentication key pair is generated by the PSD itself. This process is performed
during manufacture of a PSD.
5
The ASCOM Regional CA certificate replaces the ASCOM Manufacturing certificate already stored in each
PSD.
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The public key is extracted by ASCOM Manufacturing and transferred to the ASCOM
Regional CA (of the Factory Region) for certification.
The PSD Authentication private key is used to sign responses by a PSD to ASCOM
Manufacturing and Remote Control messages.
In the field, ASCOM Remote Control may initialize a replacement of the PSD Authentication
key pair as part of a re-keying operation. This is done by first instructing the PSD to generate a
new key pair. As a result ASCOM Remote Control receives the public key part and transfers it
to the ASCOM Regional CA for certification. After receiving the certified public key back,
ASCOM Remote Control will instruct the PSD to switch from the old key to the new one,
which will be used from then on to authenticate the PSD to the regional KMS. This operation
is integrated in an authenticated Diffie-Hellman communication session for which, in addition,
data integrity and confidentiality are protected.
5.7 ASCOM Remote Control certificate
The ASCOM Remote Control certificate is loaded into each PSD during the Authorization
phase.
The ASCOM Remote Control certificate is issued by the ASCOM Regional CA.
The ASCOM Remote Control private key is used to sign messages sent by ASCOM Remote
Control to the PSD. The PSD uses the ASCOM Remote Control certificate to verify the
ASCOM Remote Control role and any signed messages sent by the entity.
The ASCOM Remote Control certificate is only temporarily stored in the PSD. In the field,
ASCOM Remote Control may initialize a replacement of the certificate as part of a re-keying
operation. This operation is integrated in an authenticated Diffie-Hellman communication
session for which, in addition, data integrity and confidentiality are protected, see section
4.3.7.
5.8 Indicia Key Pair
The Indicia key pair is generated by the PSD itself. This process is performed in the field
during the Authorization phase.
The public key is extracted by ASCOM Remote Control and transferred to USPS IBIP key
management infrastructure for certification.
The Indicia private key is used to sign indicia data.
In the field, ASCOM Remote Control may initialize a replacement of the Indicia key pair (re-
keying). This is done by first instructing the PSD to generate a new Indicia key pair. As a
result ASCOM Remote Control receives the public key part and transfers it the same way as in
the initialization phase to the USPS IBIP key management infrastructure for certification.
After receiving the certified public key back, ASCOM Remote Control will instruct the PSD
to switch from the old Indicia key to the new one, which will be used from then on for indicia
generation. This operation is integrated in an authenticated Diffie-Hellman communication
session for which, in addition, data integrity and confidentiality are protected.
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5.9 TMS Keys
The TMS keys are symmetric keys used to mutually authenticate TMS and PSDs and to
protect the integrity of the data exchange during a postal funds download operation.
The TMS keys are session keys agreed upon by a specific PSD and TMS as part of every PSD
reset operation.
The TMS related data exchange is embedded in an authenticated Diffie-Hellman
communication session for which data integrity and confidentiality are protected.
5.10 User PIN Keys
The generation of the PSD specific initial PINs takes place during the PSD initialization step
on Ascom's premises. The PSD itself internally generates its initial PIN using the ANSI
X9.17 PRNG. After having generated the random bits followed by some formatting the PSD
outputs the initial PIN to the Ascom KMS, which stores the value in a database.
5.11 Random Number Generation
The PSD uses a ‘true’ random number generator to seed its FIPS-approved ANSI X9.17
pseudo random number generator. The output of this PRNG is used for key generation by the
PSD.
6 IBI-Lite Indicia
The PSD may also produce USPS IBI-Lite indicia. The indicia is comprised of postage
information and using the existing “TMS login ID key” to encrypt the 17-byte IBI Lite data,
then appending the triple DES encrypted data results to the IBI data to provide authenticity of
the IBI data.
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7 Annexes
7.1 References
[FIPS94] Federal Information Processing Standards Publication 140-1: Security
Requirements for Cryptographic Module, 1994.
[USPS00] United States Postal Service (USPS): Information-Based Indicia Program
(IBIP) : Performance criteria for information-based indicia and security
architecture for IBI postage metering systems. February 23, 2000 – Draft
7.2 Acronyms
CA Certification Authority
DES Data Encryption Standard
DSA Digital Signature Algorithm
FIPS PUB Federal Information Processing Standard Publication
IBI Information Based Indicia
IBIP Indicia Based Information Program
PCB Printed Circuit Board
PIN Personal Identification Number
PSD Postal Security Device
TMS TeleMeter Setting System
TLE Known as the Halser PostLink (postage meter)
MATS USPS document that maps postage meter vendor products.
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Figure 3: Neopost Organization
Mailroom Technology, Inc. Page 1 of 21
Mailroom Technology, Inc.
230 Long Hill Cross Road
Shelton, CT 06484
Mailroom Technology, Inc.
FIPS 140-1
Cryptographic Module Security Policy
for the
Mailroom Technology, Inc.
Production Postal Security Device
SAFE CV 412
Date: March 20, 2007
Version: 383SYS002C ver.6.6
File: PSD Security Policy 66.doc
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Approvals SAFE CV 412
Page ii
Approvals
Organization Responsibility Date
Engineering Name: George Brookner
Signature:
March 20 2007
Project Management Name: Don Eager
Signature:
March 20 2007
Engineering Name: Mark Ferraro
Signature:
March 20 2007
Name:
Signature:
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Change History SAFE CV 412
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Change History
Version By Changes
0.1 L. Frey First Edition
0.2 L. Frey The open questions have been transferred to a new document dedicated to that.
1.0 L. Frey First distributed version.
1.1 L. Frey Revision based on the answers to open questions (s. [s3lab3], [ASC3]) and new revision
1.3 of the SBB Specification.
1.2/1.3/1.4 Internal Review
2.0 L. Frey Release S3
lab, distributed to Ascom Hasler
2.1 L. Frey Internal Review: major modifications are:
• Use of input from
1) “Software Requirements Specification Postal Security Device”
2) “IBIP Interim Submission Concept of Operations”
3) “PSD Baseline Requirements & Architecture”
• Slight restructuring of the document using an example certificate (DS 1954
Cryptographic iButton) as background to make the security policy more “marketing
oriented” and “management readable”
• New section 4 to describe key management issues more coherent.
• No editor’s notes in the document any more. A separate document (“Underlying
assumptions” provided by S3
lab) summarizes any assumptions or open questions.
• The role/object/services concept is made more taut in order to emphasize more plain
what is the essence of the security policy, i.e. less objects and services and more
generalized items.
2.2 Internal Review
3.0 L. Frey Release S3
lab, distributed to Ascom Hasler
3.1/3.2 L. Frey Reviews, adjustment to key management concept release 0.9/DRAFT, Release to Meeting
in Shelton 10.3.99-12.3.99
4.0/4.1 L. Frey Changes due to the results of the meeting 11.3.99 in Shelton.
5.0 L. Frey Major revisions, reflecting the important changes of the USPS IBIP specifications and the
resulting modifications of the ASCOM key management system.
6.0 G. Brookner Major revision. Updated to reflect Remote Control capability of the production PSD in the
field as well as the certificate hierarchy.
Updated to reflect the Diffie-Hellman authenticated KMS session.
6.2 L. Frey Updated to include new worldwide key hierarchy structure and storage of certificates in
PSDs.
6.3 G. Brookner
M Ferraro
Clarified key zeroization, removed confidential footer, misc. spelling errors.
Updated in response to Cygnacom’s comments (07.July.2001).
6.4 R. Saunders
G. Brookner
Sections 1.1 para 4; 2.4 initialization, authorization, operation; 3.4 para 2; and 4 updated
in compliance with NIST recommendations.
Name changes from Ascom Hasler Mailing Systems to Hasler, Inc. [6/21/02].
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6.5 M.Ferraro
G. Brookner
Modified the PSD to produce USPS IBI-Lite Indicia
Added the Mapping of “SAFE CV” to marketing names
Name changes from Hasler Mailing Systems to Mailroom Technology, Inc. [2003].
All references to Ascom and Hasler map to Mailroom Technology, Inc
6.6 M.Ferraro ‘Modified the PSD, added 3 bytes of indicia information to be encrypted and reduced the
size of the encrypted data result to 3 bytes.’
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Table of Contents SAFE CV 412
Page v
Table of Contents
1 INTRODUCTION 1
1.1 Purpose 1
1.2 Terminology 1
2 PRODUCT IDENTIFICATION 2
3 PRODUCT DESCRIPTION 2
3.1 The Postal Security Device (PSD) 2
3.2 Purpose of the Postal Security Device (PSD) 3
3.3 Use of the Postal Security Device (PSD) 3
3.4 Life Cycle/Phases 4
3.5 Security Objectives of the Postal Security Device (PSD) 6
3.6 Physical Security 7
4 ROLES, SERVICES AND ACCESS CONTROL 7
4.1 Roles and Authentication 7
4.1.1 ASCOM Root CA 8
4.1.2 ASCOM Regional CA 8
4.1.2.1 Regional KMS 8
4.1.2.2 ASCOM Factory Region 8
4.1.3 ASCOM Manufacturing 8
4.1.4 ASCOM Remote Control 9
4.1.5 TMS 9
4.1.6 Customer 9
4.2 Protected Assets 10
4.2.1 PSD configuration 10
4.2.2 Indicia application configuration 10
4.2.3 Postal Funds 10
4.2.4 Customer Attributes 11
4.2.5 Statistics and Records 11
4.2.6 Cryptographic Keying Material 11
4.3 Services and Access Control Policy 11
4.3.1 General Device Initialization 13
4.3.2 Customer Specific Initialization 13
4.3.3 Funds Download 13
4.3.4 Indicia Generation 14
4.3.5 Log Extraction 14
4.3.6 Information 14
4.3.7 Management of Cryptographic Services 14
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4.3.8 Customer Authentication 15
4.4 Enabling/Disabling the Postal Security Device (PSD) 16
5 KEY MANAGEMENT 16
5.1 ASCOM Root CA certificate 18
5.2 Ephemeral Diffie-Hellman Key Pair 18
5.3 ASCOM (Factory Region) Regional CA certificate 18
5.4 ASCOM Manufacturing certificate 18
5.5 ASCOM Regional CA certificate 19
5.5.1 Region Codes 19
5.6 PSD Authentication Key Pair 19
5.7 ASCOM Remote Control certificate 20
5.8 Indicia Key Pair 20
5.9 TMS Keys 21
5.10 User PIN Keys 21
5.11 Random Number Generation 21
6 IBI-LITE INDICIA 21
7 ANNEXES 22
7.1 References 22
7.2 Acronyms 22
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Figures SAFE CV 412
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Figures
Figure 3-1: Architecture of the SAFE CV 411..................................................................................... 3
Figure 3-2: Principle Life Cycle of the PSD ........................................................................................ 5
Figure 3: Neopost Organization ........................................................................................................... 1
Tables
Table 1 SAFE CV to MATS ID Mapping............................................................................................ 2
Table 2: Protected Objects ................................................................................................................. 10
Table 3: PSD Services........................................................................................................................ 12
Table 4: Cryptographic elements stored in the PSD .......................................................................... 17
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1 Introduction
1.1 Purpose
This is a Cryptographic Module Security Policy for the MAILROOM TECHNOLOGY
INC. Postal Security Device. This policy was prepared for the purpose of a FIPS 140-1
[FIPS94] certification of the Postal Security Device. FIPS 140-1 gives U.S. Government
requirements for cryptographic modules, and defines the Security Policy as:
“A precise specification of the security rules under which the cryptographic module must
operate, including rules derived from the security requirements of this standard, and the
additional security rules imposed by the manufacturer.”
The security of the Postal Security Device meets FIPS 140-1 level 3 requirements with respect
to physical security (as specified in section 4.5 in FIPS 140-1) and level 3 in all other aspects.
Per USPS requirements, the module meets FIPS 140-1 Level 4, Environmental Failure Testing
(EFT).
This security policy describes how this is done and how the Postal Security Device is to be
used and operated in a secure fashion. The module operates only in a FIPS compliant mode
and does not support a non-FIPS mode.
1.2 Terminology
Ascom’s Secure Funds Authenticated Funds Engine (SAFE), model SAFE CV 412, will be
denoted as “PSD” throughout this document..
The Term “indicia” is used throughout this document to denote the digital Information Based
Indicia as specified by the US Postal Service. All services and functions of the PSD provided
with respect to indicia (like indicia generation, funds management and related diagnostics) are
called collectively “indicia application”.
The acronym “TMS” (for “TeleMeter Setting System”) is used to denote a certain PSD
external entity entitled to perform privileged operations on the indicia application (like
downloading of funds).
The acronym “KMS” (for “Key Management System”) is used to denote a certain PSD
external entity entitled to perform privileged operations related to the management of
cryptographic material.
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2 Product Identification
The devices will be identified as SAFE CV 412. This identification will be extended across
various marketing models.
The following table maps the “SAFE CV” Software version number to USPS MATS ID’s and
Neopost/Hasler Marketing Names.
Note: There are no products currently using the CV 412 device.
SAFE CV 412 Software
Version
Marketing Name
X X V3.3.2
X X V3.3.3
Table 1 SAFE CV to MATS ID Mapping
3 Product Description
3.1 The Postal Security Device (PSD)
The PSD device is a multiple chip embedded module designed as a single electronic circuit
board with interfaces to a serial external port and a power supply. The board is enclosed with a
tamper detecting “continuity” mesh and sealed in a hard opaque heat transferring potting
compound. Together these elements both conceal the electronic circuitry and provide for
tamper detection and response. Further, tampering cannot occur without significant visual
damage to the potting material, board or board components. No physical access to the PSD
(e.g. battery replacement) is possible.
The main processor executes a static application. The primary objective of this application is
to protect the Postal funds and to apply respective access rules. Various memory components
and supporting processors (like cryptographic processors) are used.
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The general architecture of the PSD is depicted in the following diagram.
Figure 3-1: Architecture of the SAFE CV 412
3.2 Purpose of the Postal Security Device (PSD)
The PSD supports the creation of authorized indicia, which shows evidence of postage
payment. The indicia consists of a two-dimensional bar code and certain human readable
information such as a Device ID Number, date of mailing, amount of postage, mailer’s
location (city & state or ZIP Code) and rate category.
The PSD provides for the accurate accounting of postal funds. It holds the funds needed for
the postage and produces on request of the USPS customer digitally signed data sets, each
representing indicia. It is designed to adhere to applicable USPS regulations [USPS00].
3.3 Use of the Postal Security Device (PSD)
The PSD is integrated in or connected to some host system under the custody of the customer
(like a PC or within a metering/mailing device). The customer may access the PSD and
instruct it to generate indicia on his behalf by using some application software running on the
host system. The indicia will be used by the host system to produce the actual printed indicia
on mail pieces with suitable printers.
The host system also provides a communication link (e.g. using a modem) to certain external
entities with administrative or application related privileged responsibilities. These entities are
part of the background infrastructure provided by ASCOM.
Crypto Boundary
Power
protection
Circuitry
Opto Isolator
Flash
Memory
Chip
Select
Unit
Bus
Interface
Unit
PIO Unit
CPU
Core
Serial
Port 1
Serial
Port 0
Clock/Pwr
Mgmt Unit
Interrupt
Control
Unit
Timer
Control
Unit
Main Processor
I/O
Connector
Misc.
Logic
Internal
Comm
MUX
Crypto Processor
True Random No. Generator
Crypto Coprocessor
Security Sensors
Power on/off Reset
Serial Interface
CPU Core
Program Memory
EEPROM
Timers
Crypto Processor
Power
Supervisor
Tamper
Detection/
Response
Battery
Flash
Memory
Real-Time
Clock
SRAM
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The ASCOM Telemeter Setting ® (TMS ®) data center is responsible for the (remote)
download of new postal funds, the upload of audit information and other application
management related operations.
ASCOM Regional CA and ASCOM Remote Control acting as administrators may access the
PSD in the field (remotely) and are allowed to manage cryptographic elements.
ASCOM may perform diagnostic operations with a PSD when it is returned from the customer
to ASCOM, thereafter leading to the PSD being re-manufactured or scrapped.
The communication between the PSD and any of those privileged entities introduced before
are protected by cryptographic means. The PSD itself has a secure containment.
The entity “KMS” or more precisely its logical constituents ASCOM Regional CA, ASCOM
Remote Control and TMS may access the PSD in the field (remotely) and are allowed to
provide such operations as changing cryptographic keys, disabling PSDs, providing secure
session operations for the exchange of protected data with the PSD. These processes provide
authentication, integrity protection and encryption means for said data interchanges.
3.4 Life Cycle/Phases
The PSD is manufactured and initialized at ASCOM facilities and then delivered to customers
for operational use in the field. The PSD returns for decommissioning or for failures reported
by the customer to ASCOM. As necessary, ASCOM may recover any postal funds stored in
the PSD and arrange for the crediting of the respective amount to the customer.
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Manufacturing
Manufacturing
Initialization
Initialization
Authorization
Authorization
Operation
Operation
Return
Return
ASCOM
Field
Re-Keying
Re-Authorization
Figure 3-2: Principle Life Cycle of the PSD
Manufacturing of the PSD is done in ASCOM facilities and consists of basic preparations of
the PSD for its later use. This includes primarily the identification of the PCB and the
initialization of the PCB’s internal clock. Then, the enclosure is put on the PCB making the
PSD ready for initialization.
Initialization makes the PSD ready for shipment into the field. This process, which also takes
place on ASCOM premises, basically includes the following steps:
5. Loading and initialization of the actual IBIP application software and related data.
6. Initialization of PSD Authentication Keys used to establish a secure communication later
on between a PSD in the field and the ASCOM infrastructure.
7. Initialization of the PIN keys used for secure transmission of the PIN for Customer
authentication to the PSD.
8. Loading of cryptographic certificates used to authenticate administrative roles.
From now on and until returned to ASCOM, the PSD is regarded as being in a potential hostile
environment (the “field”). The PSD protects all assets including the postal funds,
cryptographic material and available services according to the rules presented herein. Roles
and Services are described subsequently.
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An authorized dealer may ship the PSD to the customer as an alternative to direct shipment
from ASCOM.
In the Authorization phase, a given PSD is assigned to a specific customer whose attributes
are put into the PSD. Related (external) registration activities take place to make the PSD and
the relationship to the given customer known to the background infrastructure (ASCOM and
TMS). The PSD is now ready to be used by the customer from a technical point of view, but
has still no postal funds in it.
In the Operation phase, the first step is to load postal funds into the PSD, which is done by
TMS. The customer may produce digital Information Based Indicia now, using the available
postal funds at his discretion. During the operational use of the PSD, the TMS will
communicate with the PSD from time to time in order to download new postal funds and to
audit the device.
A PSD in the field may run through a new, partial Authorization (referred to as Re-
Authorization), remotely controlled by ASCOM, if arises (e.g. due to changed customer data
as address).
A PSD in the field may undergo Re-Keying, remotely controlled by ASCOM Remote
Control. During this phase all or part of the cryptographic keying material (private keys,
public key certificates) stored by the PSD may be replaced by new one.
The PSD may be returned for regular de-commissioning or other reasons (e.g. technical
failure, suspected tampering) to ASCOM. ASCOM may access the PSD for diagnostic
purpose and in order to recover the customer’s postal funds stored in the PSD. However, the
PSD prevents any access to secret or private keys in that procedure. The SAFE’s internal
hardware and connections are not replaceable. Any defect is unserviceable. Depending upon
the operational status of the PSD, it may either be destroyed or sent through the manufacturing
and initialization process.
3.5 Security Objectives of the Postal Security Device (PSD)
The PSD is primarily a secure device holding an amount of postal funds, which the USPS
customer currently possessing the PSD may use to produce digital Information Based Indicia.
The following assertions apply to the PSD:
A9 The major asset contained in the PSD is the current amount of postal funds stored
in it.
A10 The customer may request the PSD to create digital Information Based Indicia.
A11 The PSD enforces the proper reduction of the available amount of postal funds as
part of producing a digital Information Based Indicia.
A12 The downloading of new postal funds may be initiated by the customer but not
influenced otherwise. The downloading is done by TMS.
A13 The customer may recognize the status of the postal funds and the PSD in general.
A14 Initial cryptographic data (e.g. keys, certificates and relevant cryptographic
parameters) required for authentication is initialized on ASCOM premises in a
secure environment controlled by ASCOM Manufacturing.
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A15 Cryptographic keys or certificates may be changed in the field. This is an
administrative responsibility of ASCOM KMS entities (e.g. ASCOM Regional CA
and/or ASCOM Remote Control).
A16 Secret and private keys needed to enforce these security objectives never leave the
PSD.
These security objectives are fulfilled by the PSD by authenticating the respective roles and
using the caller’s role as reference for controlling the use of services and access to assets. This
is done each time a service is requested from the PSD.
3.6 Physical Security
The physical security of the PSD will be governed by the physical security requirements of
FIPS PUB 140-1 Level 3. The security boundary of the PSD is encapsulated within a plastic
enclosure filled with hard opaque potting material. There is no access to the internal
components without showing tamper evidence. The potting material offers a high degree of
tamper resistance, causing physical destruction to components if removal is attempted. The
PSD also utilizes tamper detection countermeasures that respond to tampering by zeroing
cryptographic keys and disabling the PSD from further use.
4 Roles, Services and Access Control
4.1 Roles and Authentication
Certain roles are identified by the PSD for the purpose of allowing access to services:
• ASCOM Root CA,
• ASCOM Regional CA,
• ASCOM Manufacturing,
• ASCOM Remote Control,
• TMS,
• Customer.
ASCOM Root CA is the highest level of authority in the certificate hierarchy and is the
identity that assumes the Crypto Officer role that is enacted to issue all ASCOM Regional CA
certificates used by the PSD to authenticate regional KMS entities. ASCOM Root CA also
signs PSD-resident applications.
Both entities, ASCOM Regional CA and ASCOM Remote Control, may access the PSD in the
field for the purpose of the management of cryptographic elements in the PSD and thus
represent the “Crypto Officer” during the operational phase of the PSD.
ASCOM Manufacturing has the responsibility for initializing the PSD with cryptographic
keying material during the manufacturing and initialization phase. ASCOM Manufacturing
thus represents the “Crypto Officer” on ASCOM premises. ASCOM Manufacturing may
never access a PSD in the field.
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TMS and Customer represent the “User” of the PSD, specifically the user of the indicia
application. Some services with an informative purpose only are provided by the PSD in the
field and may be requested by an entity at any time (e.g. Licensing Zipcode, Account Number,
Customer Type, Daylight Savings, Time Zone (Local Time), PSD Owner). The external entity
calling these services is not expected to explicitly represent a certain role to the PSD.
4.1.1 ASCOM Root CA
ASCOM Root CA represents the highest cryptographic authority of the key management
system run by ASCOM for the indicia application and as such issues all certificates of the next
lower level of the KMS, i.e. the ASCOM Regional CA certificates.
The self-signed certificate of ASCOM Root CA is stored in each PSD.
4.1.2 ASCOM Regional CA
ASCOM Regional CA represents the highest cryptographic authority of a KMS for a single
country or region of a country.
It acts as the Certification Authority for its population of PSDs and the other regional KMS
entities.
ASCOM Hasler maintains control over the Region Change process. No Regional KMS can
take over control of PSDs that belong to a different Regional KMS. All PSDs that are shipped
from ASCOM Hasler Manufacturing are "generic" and can be assigned to any region. But any
PSD assigned to a particular region can change its region only back to ASCOM Hasler
Manufacturing.
4.1.2.1 Regional KMS
A regional KMS supports all PSDs within a single country or defined region of that country
(excluding the ASCOM Factory Region). As the highest local cryptographic authority, the
ASCOM Regional CA issues all Remote Control certificates and issues all PSD
Authentication certificates in that particular region.
4.1.2.2 ASCOM Factory Region
The Factory Region is a dedicated regional KMS introduced to provide the cryptographic
support for the manufacturing and initialization of new PSDs and the return of PSDs from the
field. The structure of its KMS is identical to the one of any other regional KMS. Thus, the
Factory Region has its own ASCOM Regional CA that signs all ASCOM Manufacturing
certificates. It also issues the PSD Authentication certificate for a PSD under manufacture.
4.1.3 ASCOM Manufacturing
ASCOM Manufacturing represents the manufacturer of the PSD and is responsible for all
activities applied to the PSD within the premises of ASCOM (manufacturing, initialization
and return procedures). The Manufacturing entity exists only in the Factory Region, and
authenticates the KMS to a PSD under manufacture, or after its return from a customer.
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4.1.4 ASCOM Remote Control
ASCOM Remote Control directly or on behalf of ASCOM Regional CA, is authorized and
responsible for accessing the PSD for various administrative purposes in the field. This
includes:
• initiating the generation of a new indicia key pair (re-keying),
• resetting the customer’s PIN,
• loading the customer specific data in the (Re)-Authorization phase,
• enabling or disabling the indicia application and
• extracting indicia application related statistic and logfiles 6
.
Each message from ASCOM Remote Control is authenticated by the PSD. In particular, all
messages exchanged for the purpose of replacing an indicia key pair are protected by
cryptographic means. While digital signatures provide entity authentication and data integrity,
data confidentiality is protected by symmetric encryption.
4.1.5 TMS
TMS is responsible for controlling the postal funds in the PSD. TMS may only download new
postal funds and activate or deactivate the indicia creation service. This is supported by an
automatic watchdog mechanism in the PSD enforcing a periodical audit of the PSD’s funds
related services by TMS.
Cryptographic means are used as part of a specific protocol (TMS-II protocol) to authenticate
the respective sender of messages (TMS or the PSD) and to protect the data integrity and (if
needed) confidentiality of the message exchanges.
The security of the TMS-II protocol is based on the following features:
• prevention of message replaying by the use of Triple DES session keys and time variant
parameters,
• mutual authentication of both the PSD and TMS,
• transaction data integrity using a DESMAC for each message,
• selective confidentiality for parts of the message as appropriate.
4.1.6 Customer
The Customer is allowed to use the PSD to produce indicia, which consumes the available
postal funds in the PSD. In order to do so he has to perform a “login” into the PSD by
presenting a PIN, which identifies him/her (for details see section 4.3.8).
6
This may take place in the field, but will also be done as the first step in the Return phase.
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4.2 Protected Assets
The major asset held in the PSD is the currently available amount of postal funds. Several
more objects are identified in order to provide a more detailed picture of the PSD’s access
control policy.
Table 5: Protected Objects
PSD configuration
Indicia application configuration
Postal funds
Customer attributes
PIN
Statistics and records
Cryptographic keying material
4.2.1 PSD configuration
Hardware and software of the PSD are configured in the manufacturing and initialization
phase on ASCOM’s premises. The PSD configuration is the hardware and software along with
more basic operational parameters and data objects of the PSD in the field 7
. Operational
parameters and data objects include for example date and time (along with related parameters)
and any data identifying the hardware and software (e.g. meter serial number).
Any modification of the hardware/software of a PSD having been in the field requires the
return of the device to ASCOM facilities beforehand, following proper return procedures (see
section 3.4).
4.2.2 Indicia application configuration
Various parameters, some of them being defined specifically for a customer, are used to
control the indicia application. These parameters include various limits applied when
performing indicia related transactions.
4.2.3 Postal Funds
The most important data item managed by the indicia application is the amount of postal
funds, which is available for consumption via indicia generation. Specific security
requirements imposed by USPS apply to the postal funds related management functions and
access methods. The postal funds are decreased every time an indicium is generated and
increased by a TMS originated download of new funds.
7
It is this configuration, which is primarily subject to security policy considerations in this document.
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4.2.4 Customer Attributes
Various attributes are used to identify and describe the customer. These customer attributes
include a license ID, a corresponding ZIP code and the Customer’s accounting number used
by TMS for accounting purposes.
4.2.5 Statistics and Records
The PSD maintains various statistics and records about the use of services related to the postal
funds and indicia generation. These statistics and records include recent transactions and
various events as reaching application related limits, funds transfers from TMS, errors,
warnings and the modification of parameters related to those services.
4.2.6 Cryptographic Keying Material
The indicia are primarily secured by a digital signature generated with a dedicated private key
stored in the PSD. Other cryptographic keys are used to authenticate the entities ASCOM CA,
ASCOM Regional CA, ASCOM Remote Control and ASCOM Manufacturing. Domain
parameters used by any cryptographic mechanisms are also regarded as being a part of the
cryptographic keying material8
.
Keys and certificates stored in a PSD consist of:
• ASCOM Root CA certificate,
• ASCOM (Factory Region) Regional CA certificate (temporarily),
• ASCOM Regional CA certificate,
• ASCOM Manufacturing certificate (temporarily),
• ASCOM Remote Control certificate (temporarily),
• PSD Authentication certificate and the corresponding private key,
• Indicia certificate and private key,
• User PIN Keys,
• TMS keys,
• Ephemeral Diffie-Hellman keys (temporarily).
4.3 Services and Access Control Policy
The PSD provides various services to external entities as presented in Table 3 and described
hereafter.
Note: This security policy focuses on the PSDs in the field (see sect. 3.4). References to
manufacturing related phases (Manufacturing and Initialization) as well as to the Return phase
are made here only to provide the reader with a complete picture of the overall life cycle.
8
The meaning and use of the cryptographic keying material is described in more detail in Section 4.3.7 and
Section 5.
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Table 6: PSD Services
Service Roles Access allowed for Life cycle
phase
C.O. User
General Device
Initialization
X ASCOM Manufacturing Initialization
Customer
Specific
Initialization
X ASCOM Remote Control Authorization
Funds
Download
X TMS Operation
Indicia
Generation
X Customer Operation
Generate
Indicia Key Pair
X ASCOM Remote Control
(ASCOM Manufacturing)
Authorization
(Return)
Get Indicia
Public Key
X ASCOM Remote Control
(ASCOM Manufacturing)
Authorization
(Return)
Generate
Authentication
Key Pair
X ASCOM Manufacturing Initialization
Get
Authentication
Public Key
X ASCOM Manufacturing Initialization
Generate Diffie-
Hellman Key
Exchange for
TDES Session
Key Creation
X X ASCOM Manufacturing
ASCOM Remote Control
TMS
Initialization
Authorization
Operation
Generate PIN
Keys
X X ASCOM Manufacturing
Customer
Initialization
Operation
Generate TMS
Keys
X TMS Operation
Get Certificates X ASCOM Manufacturing
ASCOM Remote Control
Initialization
Authorization
Log Extraction X ASCOM Remote Control
(ASCOM Manufacturing)
Operation
(Return)
Information X X All Operation
(Return)
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Management of
Cryptographic
Services
X ASCOM Remote Control
(ASCOM Manufacturing)
Operation
(Initialization/
Return)
Customer
Authentication
X X Customer (see section 4.3.8) and ASCOM
Remote Control
Operation
Enabling/Disabl
ing the PSD
X X TMS and
ASCOM Remote Control
Operation
4.3.1 General Device Initialization
ASCOM Manufacturing will initialize the PSD device when it leaves the Manufacturing
phase. This process will initialize the indicia application along with all its related data
completely as defined by ASCOM Manufacturing. The new application is loaded into the PSD
as part of the functions related to this service.
ASCOM Manufacturing, in the initialization phase of the PSD, uses certain special diagnostic
applications and other initialization applications in order to initialize various data objects and
finally to load the indicia application which provides the control for use of the PSD in the
field.
Data to be initialized includes the current date, time and attributes which identify and describe
the specific device.
4.3.2 Customer Specific Initialization
This service includes functions performed by ASCOM Remote Control in the field in order to
configure the PSD for the use with a specific customer.
This includes loading of attributes identifying and describing the specific customer. It also
includes the setting of values for parameters, which are specific for the customer and are
recognized by the indicia application in operation (e.g. limits for new funds).
4.3.3 Funds Download
TMS may access the PSD in the field through the KMS functional entity for downloading of
new funds. The communications with the PSD and the related exchange of TMS data is
accommodated via the cryptographically secured messaging mechanism specified in section
4.3.7.
TMS carries out the following operations as part of the funds downloading operation:
• receives a request for download of new funds and grants new funds after having performed
suitable checks and
• performs a check of the value of postal funds in the PSD allowing TMS to compare it with
available information for correctness (“device audit”);
• reads various values and parameters of the PSD configuration, the Indicia application
configuration and the customer attributes;
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• may modify the PSD’s date-and-time;
• releases the PSD for further use.
The PSD tracks the remaining amount of available funds and the total amount of funds used
for indicia creation9
.
A PSD internal Watchdog timer is used to automatically inhibit further indicia creations until
proper audit is done.
The TMS provides the accounting services necessary to support USPS funds management
requirements.
4.3.4 Indicia Generation
The Customer may generate indicia using the available funds [USPS00]. The creation of
indicia decreases the available amount of funds while it increases the overall sum of funds
used. Any other change of the funds is restricted to TMS.
A precondition for indicia generation is that the PSD indicia application function is not
disabled because of an overdue audit (see section 4.3.3).
4.3.5 Log Extraction
ASCOM Remote Control may extract Statistics and Records from PSDs in the field for
diagnostic purposes, while ASCOM Manufacturing may extract this data as part of the Return
procedures.
4.3.6 Information
The PSD provides service functions to access various information available in the PSD. This
information is generally not regarded as confidential. The respective service commands may
be accessed therefore without the need of a preceding authentication.
Information available includes:
• the current amount of postal funds;
• the value of various application relevant parameters (as applicable limits);
• various attributes identifying and describing the specific customer and the device;
• diagnostics and status information about the PSD device.
4.3.7 Management of Cryptographic Services
ASCOM Manufacturing and ASCOM Remote Control may query and set various elements of
the PSD’s cryptographic material (see section 4.2.6) within the context of the key management
concept described in section 5.
Available functions for ASCOM Manufacturing in the Initialization phase are:
9
These values are referred to conceptually as “descending register” and “ascending register”, see [USPS00].
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• initiate the generation of a PSD authentication key pair in a PSD and get the public key
component for certification;
• initiate the generation of the PIN keys used to decrypt the securely transmitted PIN
received for Customer authentication to the PSD,
• set and verify cryptographic parameters and certificates.
Available functions for ASCOM Remote Control in the field are:
• initiate the generation of a Indicia key pair in a PSD and get the public key component
from the PSD for certification;
• re-keying of a PSD (e.g. initiate the PSD internal generation of a new Indicia key pair);
• PSD log extraction.
The data exchanged for the purpose of the management of cryptographic services is secured
using an “authenticated Diffie-Hellman channel” with data integrity protection and symmetric
encryption.
The communications protocol used to establish the secure channel provides the following
security features:
• replay protection by using random numbers as time variant parameters;
• establishment of shared secret session keys between the two communicating entities by
Diffie-Hellman technique;
• mutual control of the shared secret keys;
• forward secrecy for the shared secret session keys (a compromised key does not put at risk
future session keys);
• authentication of the communicating parties by the use of digital signatures and
certificates;
• encryption and integrity protection through use of symmetric techniques;
• independent cryptographic keys for encryption and integrity protection.
4.3.8 Customer Authentication
The PSD is a single-user device that uses identity-based methods to authenticate its user. The
Customer is allowed to use the PSD to produce indicia that consumes the available postal
funds in the PSD. In order to do so, he has to perform a “login” into the PSD by presenting a
PIN to identify himself.
The Customer is authenticated using a PIN based mechanism. The PIN is set to a unique PSD
individual value in the Manufacturing phase. This value is made known to the customer using
a communication path different from the shipping of the PSD itself. The customer is
empowered to change the PIN when he uses the PSD the first time.
The PSD expects the customer identity PIN to be entered each time after powering up and
before using the customer role. The PSD also expects the PIN authentication procedure to be
performed again each time the synchronization at the serial interface between the PSD and the
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host system is lost. This event indicates to the PSD that it might have been moved to a
different host system.
PIN authentication must be performed, before any indicia application function (indicia
generation and TMS activities) is allowed by the PSD.
Whenever a specific consecutive number of authentication failures has occurred the PIN
authentication function is locked, which effectively prevents the access to the indicia
generation. ASCOM Remote Control may reset the PIN to its initial value.
At first power-up of an initialized PSD, the customer enters the PIN through a keypad on the
host/base. The host/base then encrypts the PIN and transfers it to the PSD. The Customer is
not forced to re-enter the PIN at each power-up since this is the only entity that accesses the
module through this interface, in the field.
The PIN is protected by encryption prior to transmission from the host/base to the PSD by
symmetric keys. This applies to both the regular entry of the current PIN and to a PIN change.
The PIN is never communicated in the clear.
The PIN keys are triple DES keys generated by the PSD and used for secure transmission of
the Customer PIN. This process is initially performed in the initialization phase.
4.4 Enabling/Disabling the Postal Security Device (PSD)
Based on several pre-defined security criteria (e.g. time, postal funds or piece count based
limits) operations of a PSD in the field may be enabled/disabled remotely by TMS and
ASCOM Remote Control, respectively, in case one or more of the criteria are met.
The battery-backed RAM contains all the security-critical data elements such as the
certificates and keys. When the electronic tamper response mechanism is activated, all the
security-critical data elements in RAM are destroyed (zeroed) thus making the PSD
inoperative.
5 Key Management
The following cryptographic elements are stored in a PSD:
• ASCOM Root CA certificate,
• ASCOM (Factory Region) Regional CA certificate (temporarily),
• ASCOM Regional CA certificate,
• ASCOM Manufacturing certificate (temporarily),
• ASCOM Remote Control certificate (temporarily),
• PSD Authentication certificate and the corresponding private key,
• Indicia certificate and private key,
• User PIN Keys,
• TMS keys,
• Ephemeral Diffie-Hellman keys (temporarily).
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Table 7: Cryptographic elements stored in the PSD
Cryptographic
element
Generation Initialization in
PSD
Usage by PSD Replacement in PSD
ASCOM Root CA
certificate
Generated by
ASCOM Root
CA
Manufacturing/
initialization phase
Verification of Regional
CA certificates.
Verification of signatures
on PSD application
binaries.
As part of re-keying
When Return application
is loaded
Ephemeral Diffie-
Hellman key pairs
Generated by
PSD
Initialization/Autho
rization/Operation
phase
(Temporarily)
Creation of session keys
for secure communication
with the KMS.
Whenever a secure
communication session is
created
ASCOM (Factory
Region) Regional
CA certificate
Issued by
ASCOM Root
CA
Manufacturing/
initialization phase
(Temporarily)
Verification of
Manufacturing Certs
(only Factory Region).
As part of Authorization
When Return application
is loaded
ASCOM
Manufacturing
certificate
Issued by
ASCOM
(Factory
Region)
Regional CA
Manufacturing/
initialization phase
(Temporarily)
Verification of ASCOM
Manufacturing and signed
data of message
exchanges with KMS.
As part of Authorization
When Return application
is loaded
ASCOM Regional
CA certificate
Issued by
ASCOM Root
CA
Authorization phase Verification of Remote
Control Certs.
As part of re-keying
When Return application
is loaded
PSD Authentication
key pair
Generated by
PSD
Initialization phase Private key signs data of
message exchanges with
regional KMS
As part of re-keying
When return application is
loaded
ASCOM Remote
Control certificate
Issued by
ASCOM
Regional CA
Authorization phase (Temporarily)
Verification of ASCOM
Remote Control and
signed data of message
exchanges with KMS.
As part of re-keying
Indicia key pair Generated by
PSD
Authorization phase Private key signs indicia
data
As part of re-keying
When Return application
is loaded
TMS keys Agreed by
PSD and TMS
Operation phase Provide mutual
authentication of TMS
and PSDs and protection
of data integrity and
confidentiality
As part of every postal
funds download operation
When Return application
is loaded
User PIN Keys Initially
Generated by
PSD
Operation phase Logon to PSD When user enters his/her
own PIN
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5.1 ASCOM Root CA certificate
The ASCOM Root CA certificate is loaded into each PSD during the Manufacturing/
Initialization phase.
The ASCOM Root CA certificate is self-signed. It contains a hash of the next public key and
the associated cryptographic domain parameters.
The security of a subsequent replacement of the ASCOM Root CA Certificate (whether
accomplished remotely, in the field, or as part of the return re-manufacturing process) is based
on the data origin authentication and integrity protection provided by the hash value (being
part of the signed data) stored in the previous version of the ASCOM Root CA certificate.
The ASCOM Root CA private key is applied to issue ASCOM Regional CA certificates and to
sign PSD application binaries.
The PSD uses the ASCOM Root CA certificate to verify subsequent ASCOM Regional CA
certificates and to check the signature on application binaries to be loaded.
The first time an application is run it is verified against this signature, then a CRC is
calculated/stored and all subsequent startups of the application verify this CRC.
5.2 Ephemeral Diffie-Hellman Key Pair
The Diffie-Hellman key pairs are initially created by the PSD during the Manufacturing/
Initialization phase. These keys are used to establish shared secrets for authenticated Diffie-
Hellman communication sessions with the KMS for which, data integrity and confidentiality
are protected, see section 4.3.7.
5.3 ASCOM (Factory Region) Regional CA certificate
The ASCOM (Factory Region) Regional CA certificate is loaded into each PSD during the
Manufacturing/Initialization phase.
The ASCOM (Factory Region) Regional CA certificate is issued by the ASCOM Root CA.
The ASCOM (Factory Region) Regional CA private key is used to issue the following
certificates:
• ASCOM Manufacturing certificates;
• PSD Authentication certificates.
The PSD uses the ASCOM (Factory Region) Regional CA certificate to verify the ASCOM
Manufacturing certificate and thus the corresponding role.
The ASCOM Regional CA certificate is only temporarily stored in the PSD and is replaced
during the Authorization phase by the ASCOM Regional CA certificate when the PSD is sent
to a destination in the field.
5.4 ASCOM Manufacturing certificate
The ASCOM Manufacturing certificate is loaded into each PSD during the Manufacturing/
Initialization phase.
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The ASCOM Manufacturing certificate is issued by the ASCOM (Factory Region) Regional
CA.
The ASCOM Manufacturing private key is used to sign messages sent by ASCOM
Manufacturing to the PSD. The PSD uses the ASCOM Manufacturing certificate to verify the
ASCOM Manufacturing role and any signed messages sent by the entity. The ASCOM
Manufacturing certificate is only temporarily stored in the PSD and is replaced during the
Authorization phase by the Remote Control certificate when the PSD is sent to a destination in
the field.
5.5 ASCOM Regional CA certificate
The ASCOM Regional CA certificate is loaded into each PSD during the Authorization
phase10
.
The ASCOM Regional CA certificate is issued by the ASCOM Root CA.
The ASCOM Regional CA private key is used to issue the following certificates:
• ASCOM Remote Control certificates (or ASCOM Manufacturing certificates for the
Factory Region);
• PSD Authentication certificates.
The PSD uses the ASCOM Regional CA certificate to verify ASCOM Remote Control
certificate and thus the corresponding role.
In the field, ASCOM Remote Control may initialize a replacement of the ASCOM Regional
CA certificate in a specific PSD as part of a re-keying operation. This operation is integrated
in an authenticated Diffie-Hellman communication session for which, in addition, data
integrity and confidentiality are protected, see section 4.3.7.
The ASCOM Regional CA certificate contains a Region Code that controls when a new
regional certificate can replace an existing regional certificate in a PSD.
5.5.1 Region Codes
A Region Change procedure is used to reconfigure a PSD when it moves from one region to
another.
Each ASCOM Regional CA certificate will contain two region codes, the "Active Region
Code" and the "Prior Region Code". These region codes act as constraints on the certificate
change process to provide the ability to configure a PSD to its regional certificate hierarchy,
reconfigure a returned PSD for ASCOM manufacturing, and not allow a regional KMS to
reconfigure a PSD for a different region, cf. section 4.1.2.
5.6 PSD Authentication Key Pair
The PSD Authentication key pair is generated by the PSD itself. This process is performed
during manufacture of a PSD.
10
The ASCOM Regional CA certificate replaces the ASCOM Manufacturing certificate already stored in each
PSD.
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The public key is extracted by ASCOM Manufacturing and transferred to the ASCOM
Regional CA (of the Factory Region) for certification.
The PSD Authentication private key is used to sign responses by a PSD to ASCOM
Manufacturing and Remote Control messages.
In the field, ASCOM Remote Control may initialize a replacement of the PSD Authentication
key pair as part of a re-keying operation. This is done by first instructing the PSD to generate a
new key pair. As a result ASCOM Remote Control receives the public key part and transfers it
to the ASCOM Regional CA for certification. After receiving the certified public key back,
ASCOM Remote Control will instruct the PSD to switch from the old key to the new one,
which will be used from then on to authenticate the PSD to the regional KMS. This operation
is integrated in an authenticated Diffie-Hellman communication session for which, in addition,
data integrity and confidentiality are protected.
5.7 ASCOM Remote Control certificate
The ASCOM Remote Control certificate is loaded into each PSD during the Authorization
phase.
The ASCOM Remote Control certificate is issued by the ASCOM Regional CA.
The ASCOM Remote Control private key is used to sign messages sent by ASCOM Remote
Control to the PSD. The PSD uses the ASCOM Remote Control certificate to verify the
ASCOM Remote Control role and any signed messages sent by the entity.
The ASCOM Remote Control certificate is only temporarily stored in the PSD. In the field,
ASCOM Remote Control may initialize a replacement of the certificate as part of a re-keying
operation. This operation is integrated in an authenticated Diffie-Hellman communication
session for which, in addition, data integrity and confidentiality are protected, see section
4.3.7.
5.8 Indicia Key Pair
The Indicia key pair is generated by the PSD itself. This process is performed in the field
during the Authorization phase.
The public key is extracted by ASCOM Remote Control and transferred to USPS IBIP key
management infrastructure for certification.
The Indicia private key is used to sign indicia data.
In the field, ASCOM Remote Control may initialize a replacement of the Indicia key pair (re-
keying). This is done by first instructing the PSD to generate a new Indicia key pair. As a
result ASCOM Remote Control receives the public key part and transfers it the same way as in
the initialization phase to the USPS IBIP key management infrastructure for certification.
After receiving the certified public key back, ASCOM Remote Control will instruct the PSD
to switch from the old Indicia key to the new one, which will be used from then on for indicia
generation. This operation is integrated in an authenticated Diffie-Hellman communication
session for which, in addition, data integrity and confidentiality are protected.
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5.9 TMS Keys
The TMS keys are symmetric keys used to mutually authenticate TMS and PSDs and to
protect the integrity of the data exchange during a postal funds download operation.
The TMS keys are session keys agreed upon by a specific PSD and TMS as part of every PSD
reset operation.
The TMS related data exchange is embedded in an authenticated Diffie-Hellman
communication session for which data integrity and confidentiality are protected.
5.10 User PIN Keys
The generation of the PSD specific initial PINs takes place during the PSD initialization step
on Ascom's premises. The PSD itself internally generates its initial PIN using the ANSI
X9.17 PRNG. After having generated the random bits followed by some formatting the PSD
outputs the initial PIN to the Ascom KMS, which stores the value in a database.
5.11 Random Number Generation
The PSD uses a ‘true’ random number generator to seed its FIPS-approved ANSI X9.17
pseudo random number generator. The output of this PRNG is used for key generation by the
PSD.
6 IBI-Lite Indicia
The PSD may also produce USPS IBI-Lite indicia. The indicia is comprised of postage
information and using the existing “TMS login ID key” to encrypt the 17-byte IBI Lite data,
then appending the triple DES encrypted data results to the IBI data to provide authenticity of
the IBI data.
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7 Annexes
7.1 References
[FIPS94] Federal Information Processing Standards Publication 140-1: Security
Requirements for Cryptographic Module, 1994.
[USPS00] United States Postal Service (USPS): Information-Based Indicia Program
(IBIP) : Performance criteria for information-based indicia and security
architecture for IBI postage metering systems. February 23, 2000 – Draft
7.2 Acronyms
CA Certification Authority
DES Data Encryption Standard
DSA Digital Signature Algorithm
FIPS PUB Federal Information Processing Standard Publication
IBI Information Based Indicia
IBIP Indicia Based Information Program
PCB Printed Circuit Board
PIN Personal Identification Number
PSD Postal Security Device
TMS TeleMeter Setting System
TLE Known as the Halser PostLink (postage meter)
MATS USPS document that maps postage meter vendor products.
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Figure 3: Neopost Organization
Mailroom Technology, Inc. Page 1 of 21
Mailroom Technology, Inc.
230 Long Hill Cross Road
Shelton, CT 06484
Mailroom Technology, Inc.
FIPS 140-1
Cryptographic Module Security Policy
for the
Mailroom Technology, Inc.
Production Postal Security Device
SAFE CV 413
Date: 20 March 2007
Version: 383SYS002A ver.6.6
File: PSD Security Policy 66.doc
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Approvals SAFE CV 413
Page ii
Approvals
Organization Responsibility Date
Engineering Name: George Brookner
Signature:
March 20 2007
Project Management Name: Don Eager
Signature:
March 20 2007
Engineering Name: Mark Ferraro
Signature:
March 20 2007
Name:
Signature:
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Change History
Version By Changes
0.1 L. Frey First Edition
0.2 L. Frey The open questions have been transferred to a new document dedicated to that.
1.0 L. Frey First distributed version.
1.1 L. Frey Revision based on the answers to open questions (s. [s3lab3], [ASC3]) and new revision
1.3 of the SBB Specification.
1.2/1.3/1.4 Internal Review
2.0 L. Frey Release S3
lab, distributed to Ascom Hasler
2.1 L. Frey Internal Review: major modifications are:
• Use of input from
1) “Software Requirements Specification Postal Security Device”
2) “IBIP Interim Submission Concept of Operations”
3) “PSD Baseline Requirements & Architecture”
• Slight restructuring of the document using an example certificate (DS 1954
Cryptographic iButton) as background to make the security policy more “marketing
oriented” and “management readable”
• New section 4 to describe key management issues more coherent.
• No editor’s notes in the document any more. A separate document (“Underlying
assumptions” provided by S3
lab) summarizes any assumptions or open questions.
• The role/object/services concept is made more taut in order to emphasize more plain
what is the essence of the security policy, i.e. less objects and services and more
generalized items.
2.2 Internal Review
3.0 L. Frey Release S3
lab, distributed to Ascom Hasler
3.1/3.2 L. Frey Reviews, adjustment to key management concept release 0.9/DRAFT, Release to Meeting
in Shelton 10.3.99-12.3.99
4.0/4.1 L. Frey Changes due to the results of the meeting 11.3.99 in Shelton.
5.0 L. Frey Major revisions, reflecting the important changes of the USPS IBIP specifications and the
resulting modifications of the ASCOM key management system.
6.0 G. Brookner Major revision. Updated to reflect Remote Control capability of the production PSD in the
field as well as the certificate hierarchy.
Updated to reflect the Diffie-Hellman authenticated KMS session.
6.2 L. Frey Updated to include new worldwide key hierarchy structure and storage of certificates in
PSDs.
6.3 G. Brookner
M Ferraro
Clarified key zeroization, removed confidential footer, misc. spelling errors.
Updated in response to Cygnacom’s comments (07.July.2001).
6.4 R. Saunders
G. Brookner
Sections 1.1 para 4; 2.4 initialization, authorization, operation; 3.4 para 2; and 4 updated
in compliance with NIST recommendations.
Name changes from Ascom Hasler Mailing Systems to Hasler, Inc. [6/21/02].
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6.5 M.Ferraro
G. Brookner
Modified the PSD to produce USPS IBI-Lite Indicia
Added the Mapping of “SAFE CV” to marketing names
Name changes from Hasler Mailing Systems to Mailroom Technology, Inc. [2003].
All references to Ascom and Hasler map to Mailroom Technology, Inc
6.6 M.Ferraro ‘Modified the PSD, added 3 bytes of indicia information to be encrypted and reduced the
size of the encrypted data result to 3 bytes.’
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Table of Contents
1 INTRODUCTION 1
1.1 Purpose 1
1.2 Terminology 1
2 PRODUCT IDENTIFICATION 2
3 PRODUCT DESCRIPTION 2
3.1 The Postal Security Device (PSD) 2
3.2 Purpose of the Postal Security Device (PSD) 3
3.3 Use of the Postal Security Device (PSD) 3
3.4 Life Cycle/Phases 4
3.5 Security Objectives of the Postal Security Device (PSD) 6
3.6 Physical Security 7
4 ROLES, SERVICES AND ACCESS CONTROL 7
4.1 Roles and Authentication 7
4.1.1 ASCOM Root CA 8
4.1.2 ASCOM Regional CA 8
4.1.2.1 Regional KMS 8
4.1.2.2 ASCOM Factory Region 8
4.1.3 ASCOM Manufacturing 8
4.1.4 ASCOM Remote Control 9
4.1.5 TMS 9
4.1.6 Customer 9
4.2 Protected Assets 10
4.2.1 PSD configuration 10
4.2.2 Indicia application configuration 10
4.2.3 Postal Funds 10
4.2.4 Customer Attributes 11
4.2.5 Statistics and Records 11
4.2.6 Cryptographic Keying Material 11
4.3 Services and Access Control Policy 11
4.3.1 General Device Initialization 13
4.3.2 Customer Specific Initialization 13
4.3.3 Funds Download 13
4.3.4 Indicia Generation 14
4.3.5 Log Extraction 14
4.3.6 Information 14
4.3.7 Management of Cryptographic Services 14
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4.3.8 Customer Authentication 15
4.4 Enabling/Disabling the Postal Security Device (PSD) 16
5 KEY MANAGEMENT 16
5.1 ASCOM Root CA certificate 18
5.2 Ephemeral Diffie-Hellman Key Pair 18
5.3 ASCOM (Factory Region) Regional CA certificate 18
5.4 ASCOM Manufacturing certificate 18
5.5 ASCOM Regional CA certificate 19
5.5.1 Region Codes 19
5.6 PSD Authentication Key Pair 19
5.7 ASCOM Remote Control certificate 20
5.8 Indicia Key Pair 20
5.9 TMS Keys 21
5.10 User PIN Keys 21
5.11 Random Number Generation 21
6 IBI-LITE INDICIA 21
7 ANNEXES 22
7.1 References 22
7.2 Acronyms 22
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Figures SAFE CV 413
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Figures
Figure 3-1: Architecture of the SAFE CV 411..................................................................................... 3
Figure 3-2: Principle Life Cycle of the PSD ........................................................................................ 5
Figure 3: Neopost Organization ........................................................................................................... 1
Tables
Table 1 SAFE CV to MATS ID Mapping............................................................................................ 2
Table 2: Protected Objects ................................................................................................................. 10
Table 3: PSD Services........................................................................................................................ 12
Table 4: Cryptographic elements stored in the PSD .......................................................................... 17
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1 Introduction
1.1 Purpose
This is a Cryptographic Module Security Policy for the MAILROOM TECHNOLOGY
INC. Postal Security Device. This policy was prepared for the purpose of a FIPS 140-1
[FIPS94] certification of the Postal Security Device. FIPS 140-1 gives U.S. Government
requirements for cryptographic modules, and defines the Security Policy as:
“A precise specification of the security rules under which the cryptographic module must
operate, including rules derived from the security requirements of this standard, and the
additional security rules imposed by the manufacturer.”
The security of the Postal Security Device meets FIPS 140-1 level 3 requirements with respect
to physical security (as specified in section 4.5 in FIPS 140-1) and level 3 in all other aspects.
Per USPS requirements, the module meets FIPS 140-1 Level 4, Environmental Failure Testing
(EFT).
This security policy describes how this is done and how the Postal Security Device is to be
used and operated in a secure fashion. The module operates only in a FIPS compliant mode
and does not support a non-FIPS mode.
1.2 Terminology
Ascom’s Secure Funds Authenticated Funds Engine (SAFE), model SAFE CV 413, will be
denoted as “PSD” throughout this document..
The Term “indicia” is used throughout this document to denote the digital Information Based
Indicia as specified by the US Postal Service. All services and functions of the PSD provided
with respect to indicia (like indicia generation, funds management and related diagnostics) are
called collectively “indicia application”.
The acronym “TMS” (for “TeleMeter Setting System”) is used to denote a certain PSD
external entity entitled to perform privileged operations on the indicia application (like
downloading of funds).
The acronym “KMS” (for “Key Management System”) is used to denote a certain PSD
external entity entitled to perform privileged operations related to the management of
cryptographic material.
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2 Product Identification
The devices will be identified as SAFE CV 413. This identification will be extended across
various marketing models.
The following table maps the “SAFE CV” Software version number to USPS MATS ID’s and
Neopost/Hasler Marketing Names.
SAFE CV 413 Software
Version
Marketing Name
Neopost
PowerPost
N300 V3.3.2
PowerPost 413 V3.3.2
Hasler
Symphony
150 V3.4.0
Neopost
Symphony
N350 V3.4.0
Table 1 SAFE CV to MATS ID Mapping
3 Product Description
3.1 The Postal Security Device (PSD)
The PSD device is a multiple chip embedded module designed as a single electronic circuit
board with interfaces to a serial external port and a power supply. The board is enclosed with a
tamper detecting “continuity” mesh and sealed in a hard opaque heat transferring potting
compound. Together these elements both conceal the electronic circuitry and provide for
tamper detection and response. Further, tampering cannot occur without significant visual
damage to the potting material, board or board components. No physical access to the PSD
(e.g. battery replacement) is possible.
The main processor executes a static application. The primary objective of this application is
to protect the Postal funds and to apply respective access rules. Various memory components
and supporting processors (like cryptographic processors) are used.
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The general architecture of the PSD is depicted in the following diagram.
Figure 3-1: Architecture of the SAFE CV 413
3.2 Purpose of the Postal Security Device (PSD)
The PSD supports the creation of authorized indicia, which shows evidence of postage
payment. The indicia consists of a two-dimensional bar code and certain human readable
information such as a Device ID Number, date of mailing, amount of postage, mailer’s
location (city & state or ZIP Code) and rate category.
The PSD provides for the accurate accounting of postal funds. It holds the funds needed for
the postage and produces on request of the USPS customer digitally signed data sets, each
representing indicia. It is designed to adhere to applicable USPS regulations [USPS00].
3.3 Use of the Postal Security Device (PSD)
The PSD is integrated in or connected to some host system under the custody of the customer
(like a PC or within a metering/mailing device). The customer may access the PSD and
instruct it to generate indicia on his behalf by using some application software running on the
host system. The indicia will be used by the host system to produce the actual printed indicia
on mail pieces with suitable printers.
The host system also provides a communication link (e.g. using a modem) to certain external
entities with administrative or application related privileged responsibilities. These entities are
part of the background infrastructure provided by ASCOM.
Crypto Boundary
Power
protection
Circuitry
Opto Isolator
Flash Memory
Chip
Select
Unit
Bus
Interface
Unit
PIO Unit
CPU
Core
Serial
Port 1
Serial
Port 0
Clock/Pwr
Mgmt Unit
Interrupt
Control
Unit
Timer
Control
Unit
Main Processor
I/O
Connector
Misc.
Logic
Internal
Comm
MUX
Crypto Processor
Crypto Processor
True Random No. Generator
Crypto Coprocessor
Security Sensors
Power on/off Reset
Serial Interface
CPU Core
Program Memory
EEPROM
Timers
Crypto Processor
Power
Supervisor
Tamper
Detection/
Response
Battery
Flash
Memory
Real-Time
Clock
SRAM
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The ASCOM Telemeter Setting ® (TMS ®) data center is responsible for the (remote)
download of new postal funds, the upload of audit information and other application
management related operations.
ASCOM Regional CA and ASCOM Remote Control acting as administrators may access the
PSD in the field (remotely) and are allowed to manage cryptographic elements.
ASCOM may perform diagnostic operations with a PSD when it is returned from the customer
to ASCOM, thereafter leading to the PSD being re-manufactured or scrapped.
The communication between the PSD and any of those privileged entities introduced before
are protected by cryptographic means. The PSD itself has a secure containment.
The entity “KMS” or more precisely its logical constituents ASCOM Regional CA, ASCOM
Remote Control and TMS may access the PSD in the field (remotely) and are allowed to
provide such operations as changing cryptographic keys, disabling PSDs, providing secure
session operations for the exchange of protected data with the PSD. These processes provide
authentication, integrity protection and encryption means for said data interchanges.
3.4 Life Cycle/Phases
The PSD is manufactured and initialized at ASCOM facilities and then delivered to customers
for operational use in the field. The PSD returns for decommissioning or for failures reported
by the customer to ASCOM. As necessary, ASCOM may recover any postal funds stored in
the PSD and arrange for the crediting of the respective amount to the customer.
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Manufacturing
Manufacturing
Initialization
Initialization
Authorization
Authorization
Operation
Operation
Return
Return
ASCOM
Field
Re-Keying
Re-Authorization
Figure 3-2: Principle Life Cycle of the PSD
Manufacturing of the PSD is done in ASCOM facilities and consists of basic preparations of
the PSD for its later use. This includes primarily the identification of the PCB and the
initialization of the PCB’s internal clock. Then, the enclosure is put on the PCB making the
PSD ready for initialization.
Initialization makes the PSD ready for shipment into the field. This process, which also takes
place on ASCOM premises, basically includes the following steps:
9. Loading and initialization of the actual IBIP application software and related data.
10. Initialization of PSD Authentication Keys used to establish a secure communication later
on between a PSD in the field and the ASCOM infrastructure.
11. Initialization of the PIN keys used for secure transmission of the PIN for Customer
authentication to the PSD.
12. Loading of cryptographic certificates used to authenticate administrative roles.
From now on and until returned to ASCOM, the PSD is regarded as being in a potential hostile
environment (the “field”). The PSD protects all assets including the postal funds,
cryptographic material and available services according to the rules presented herein. Roles
and Services are described subsequently.
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An authorized dealer may ship the PSD to the customer as an alternative to direct shipment
from ASCOM.
In the Authorization phase, a given PSD is assigned to a specific customer whose attributes
are put into the PSD. Related (external) registration activities take place to make the PSD and
the relationship to the given customer known to the background infrastructure (ASCOM and
TMS). The PSD is now ready to be used by the customer from a technical point of view, but
has still no postal funds in it.
In the Operation phase, the first step is to load postal funds into the PSD, which is done by
TMS. The customer may produce digital Information Based Indicia now, using the available
postal funds at his discretion. During the operational use of the PSD, the TMS will
communicate with the PSD from time to time in order to download new postal funds and to
audit the device.
A PSD in the field may run through a new, partial Authorization (referred to as Re-
Authorization), remotely controlled by ASCOM, if arises (e.g. due to changed customer data
as address).
A PSD in the field may undergo Re-Keying, remotely controlled by ASCOM Remote
Control. During this phase all or part of the cryptographic keying material (private keys,
public key certificates) stored by the PSD may be replaced by new one.
The PSD may be returned for regular de-commissioning or other reasons (e.g. technical
failure, suspected tampering) to ASCOM. ASCOM may access the PSD for diagnostic
purpose and in order to recover the customer’s postal funds stored in the PSD. However, the
PSD prevents any access to secret or private keys in that procedure. The SAFE’s internal
hardware and connections are not replaceable. Any defect is unserviceable. Depending upon
the operational status of the PSD, it may either be destroyed or sent through the manufacturing
and initialization process.
3.5 Security Objectives of the Postal Security Device (PSD)
The PSD is primarily a secure device holding an amount of postal funds, which the USPS
customer currently possessing the PSD may use to produce digital Information Based Indicias.
The following assertions apply to the PSD:
A17 The major asset contained in the PSD is the current amount of postal funds stored
in it.
A18 The customer may request the PSD to create digital Information Based Indicias.
A19 The PSD enforces the proper reduction of the available amount of postal funds as
part of producing a digital Information Based Indicias.
A20 The downloading of new postal funds may be initiated by the customer but not
influenced otherwise. The downloading is done by TMS.
A21 The customer may recognize the status of the postal funds and the PSD in general.
A22 Initial cryptographic data (e.g. keys, certificates and relevant cryptographic
parameters) required for authentication is initialized on ASCOM premises in a
secure environment controlled by ASCOM Manufacturing.
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A23 Cryptographic keys or certificates may be changed in the field. This is an
administrative responsibility of ASCOM KMS entities (e.g. ASCOM Regional CA
and/or ASCOM Remote Control).
A24 Secret and private keys needed to enforce these security objectives never leave the
PSD.
These security objectives are fulfilled by the PSD by authenticating the respective roles and
using the caller’s role as reference for controlling the use of services and access to assets. This
is done each time a service is requested from the PSD.
3.6 Physical Security
The physical security of the PSD will be governed by the physical security requirements of
FIPS PUB 140-1 Level 3. The security boundary of the PSD is encapsulated within a plastic
enclosure filled with hard opaque potting material. There is no access to the internal
components without showing tamper evidence. The potting material offers a high degree of
tamper resistance, causing physical destruction to components if removal is attempted. The
PSD also utilizes tamper detection countermeasures that respond to tampering by zeroing
cryptographic keys and disabling the PSD from further use.
4 Roles, Services and Access Control
4.1 Roles and Authentication
Certain roles are identified by the PSD for the purpose of allowing access to services:
• ASCOM Root CA,
• ASCOM Regional CA,
• ASCOM Manufacturing,
• ASCOM Remote Control,
• TMS,
• Customer.
ASCOM Root CA is the highest level of authority in the certificate hierarchy and is the
identity that assumes the Crypto Officer role that is enacted to issue all ASCOM Regional CA
certificates used by the PSD to authenticate regional KMS entities. ASCOM Root CA also
signs PSD-resident applications.
Both entities, ASCOM Regional CA and ASCOM Remote Control, may access the PSD in the
field for the purpose of the management of cryptographic elements in the PSD and thus
represent the “Crypto Officer” during the operational phase of the PSD.
ASCOM Manufacturing has the responsibility for initializing the PSD with cryptographic
keying material during the manufacturing and initialization phase. ASCOM Manufacturing
thus represents the “Crypto Officer” on ASCOM premises. ASCOM Manufacturing may
never access a PSD in the field.
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TMS and Customer represent the “User” of the PSD, specifically the user of the indicia
application. Some services with an informative purpose only are provided by the PSD in the
field and may be requested by an entity at any time (e.g. Licensing Zipcode, Account Number,
Customer Type, Daylight Savings, Time Zone (Local Time), PSD Owner). The external entity
calling these services is not expected to explicitly represent a certain role to the PSD.
4.1.1 ASCOM Root CA
ASCOM Root CA represents the highest cryptographic authority of the key management
system run by ASCOM for the indicia application and as such issues all certificates of the next
lower level of the KMS, i.e. the ASCOM Regional CA certificates.
The self-signed certificate of ASCOM Root CA is stored in each PSD.
4.1.2 ASCOM Regional CA
ASCOM Regional CA represents the highest cryptographic authority of a KMS for a single
country or region of a country.
It acts as the Certification Authority for its population of PSDs and the other regional KMS
entities.
ASCOM Hasler maintains control over the Region Change process. No Regional KMS can
take over control of PSDs that belong to a different Regional KMS. All PSDs that are shipped
from ASCOM Hasler Manufacturing are "generic" and can be assigned to any region. But any
PSD assigned to a particular region can change its region only back to ASCOM Hasler
Manufacturing.
4.1.2.1 Regional KMS
A regional KMS supports all PSDs within a single country or defined region of that country
(excluding the ASCOM Factory Region). As the highest local cryptographic authority, the
ASCOM Regional CA issues all Remote Control certificates and issues all PSD
Authentication certificates in that particular region.
4.1.2.2 ASCOM Factory Region
The Factory Region is a dedicated regional KMS introduced to provide the cryptographic
support for the manufacturing and initialization of new PSDs and the return of PSDs from the
field. The structure of its KMS is identical to the one of any other regional KMS. Thus, the
Factory Region has its own ASCOM Regional CA that signs all ASCOM Manufacturing
certificates. It also issues the PSD Authentication certificate for a PSD under manufacture.
4.1.3 ASCOM Manufacturing
ASCOM Manufacturing represents the manufacturer of the PSD and is responsible for all
activities applied to the PSD within the premises of ASCOM (manufacturing, initialization
and return procedures). The Manufacturing entity exists only in the Factory Region, and
authenticates the KMS to a PSD under manufacture, or after its return from a customer.
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4.1.4 ASCOM Remote Control
ASCOM Remote Control directly or on behalf of ASCOM Regional CA, is authorized and
responsible for accessing the PSD for various administrative purposes in the field. This
includes:
• initiating the generation of a new indicia key pair (re-keying),
• resetting the customer’s PIN,
• loading the customer specific data in the (Re)-Authorization phase,
• enabling or disabling the indicia application and
• extracting indicia application related statistic and logfiles 11
.
Each message from ASCOM Remote Control is authenticated by the PSD. In particular, all
messages exchanged for the purpose of replacing an indicia key pair are protected by
cryptographic means. While digital signatures provide entity authentication and data integrity,
data confidentiality is protected by symmetric encryption.
4.1.5 TMS
TMS is responsible for controlling the postal funds in the PSD. TMS may only download new
postal funds and activate or deactivate the indicia creation service. This is supported by an
automatic watchdog mechanism in the PSD enforcing a periodical audit of the PSD’s funds
related services by TMS.
Cryptographic means are used as part of a specific protocol (TMS-II protocol) to authenticate
the respective sender of messages (TMS or the PSD) and to protect the data integrity and (if
needed) confidentiality of the message exchanges.
The security of the TMS-II protocol is based on the following features:
• prevention of message replaying by the use of Triple DES session keys and time variant
parameters,
• mutual authentication of both the PSD and TMS,
• transaction data integrity using a DESMAC for each message,
• selective confidentiality for parts of the message as appropriate.
4.1.6 Customer
The Customer is allowed to use the PSD to produce indicia, which consumes the available
postal funds in the PSD. In order to do so he has to perform a “login” into the PSD by
presenting a PIN, which identifies him/her (for details see section 4.3.8).
11
This may take place in the field, but will also be done as the first step in the Return phase.
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4.2 Protected Assets
The major asset held in the PSD is the currently available amount of postal funds. Several
more objects are identified in order to provide a more detailed picture of the PSD’s access
control policy.
Table 8: Protected Objects
PSD configuration
Indicia application configuration
Postal funds
Customer attributes
PIN
Statistics and records
Cryptographic keying material
4.2.1 PSD configuration
Hardware and software of the PSD are configured in the manufacturing and initialization
phase on ASCOM’s premises. The PSD configuration is the hardware and software along with
more basic operational parameters and data objects of the PSD in the field 12
. Operational
parameters and data objects include for example date and time (along with related parameters)
and any data identifying the hardware and software (e.g. meter serial number).
Any modification of the hardware/software of a PSD having been in the field requires the
return of the device to ASCOM facilities beforehand, following proper return procedures (see
section 3.4).
4.2.2 Indicia application configuration
Various parameters, some of them being defined specifically for a customer, are used to
control the indicia application. These parameters include various limits applied when
performing indicia related transactions.
4.2.3 Postal Funds
The most important data item managed by the indicia application is the amount of postal
funds, which is available for consumption via indicia generation. Specific security
requirements imposed by USPS apply to the postal funds related management functions and
access methods. The postal funds are decreased every time an indicium is generated and
increased by a TMS originated download of new funds.
12
It is this configuration, which is primarily subject to security policy considerations in this document.
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4.2.4 Customer Attributes
Various attributes are used to identify and describe the customer. These customer attributes
include a license ID, a corresponding ZIP code and the Customer’s accounting number used
by TMS for accounting purposes.
4.2.5 Statistics and Records
The PSD maintains various statistics and records about the use of services related to the postal
funds and indicia generation. These statistics and records include recent transactions and
various events as reaching application related limits, funds transfers from TMS, errors,
warnings and the modification of parameters related to those services.
4.2.6 Cryptographic Keying Material
The indicia are primarily secured by a digital signature generated with a dedicated private key
stored in the PSD. Other cryptographic keys are used to authenticate the entities ASCOM CA,
ASCOM Regional CA, ASCOM Remote Control and ASCOM Manufacturing. Domain
parameters used by any cryptographic mechanisms are also regarded as being a part of the
cryptographic keying material13
.
Keys and certificates stored in a PSD consist of:
• ASCOM Root CA certificate,
• ASCOM (Factory Region) Regional CA certificate (temporarily),
• ASCOM Regional CA certificate,
• ASCOM Manufacturing certificate (temporarily),
• ASCOM Remote Control certificate (temporarily),
• PSD Authentication certificate and the corresponding private key,
• Indicia certificate and private key,
• User PIN Keys,
• TMS keys,
• Ephemeral Diffie-Hellman keys (temporarily).
4.3 Services and Access Control Policy
The PSD provides various services to external entities as presented in Table 3 and described
hereafter.
Note: This security policy focuses on the PSDs in the field (see sect. 3.4). References to
manufacturing related phases (Manufacturing and Initialization) as well as to the Return phase
are made here only to provide the reader with a complete picture of the overall life cycle.
13
The meaning and use of the cryptographic keying material is described in more detail in Section 4.3.7 and
Section 5.
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Table 9: PSD Services
Service Roles Access allowed for Life cycle
phase
C.O. User
General Device
Initialization
X ASCOM Manufacturing Initialization
Customer
Specific
Initialization
X ASCOM Remote Control Authorization
Funds
Download
X TMS Operation
Indicia
Generation
X Customer Operation
Generate
Indicia Key Pair
X ASCOM Remote Control
(ASCOM Manufacturing)
Authorization
(Return)
Get Indicia
Public Key
X ASCOM Remote Control
(ASCOM Manufacturing)
Authorization
(Return)
Generate
Authentication
Key Pair
X ASCOM Manufacturing Initialization
Get
Authentication
Public Key
X ASCOM Manufacturing Initialization
Generate Diffie-
Hellman Key
Exchange for
TDES Session
Key Creation
X X ASCOM Manufacturing
ASCOM Remote Control
TMS
Initialization
Authorization
Operation
Generate PIN
Keys
X X ASCOM Manufacturing
Customer
Initialization
Operation
Generate TMS
Keys
X TMS Operation
Get Certificates X ASCOM Manufacturing
ASCOM Remote Control
Initialization
Authorization
Log Extraction X ASCOM Remote Control
(ASCOM Manufacturing)
Operation
(Return)
Information X X All Operation
(Return)
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Management of
Cryptographic
Services
X ASCOM Remote Control
(ASCOM Manufacturing)
Operation
(Initialization/
Return)
Customer
Authentication
X X Customer (see section 4.3.8) and ASCOM
Remote Control
Operation
Enabling/Disabl
ing the PSD
X X TMS and
ASCOM Remote Control
Operation
4.3.1 General Device Initialization
ASCOM Manufacturing will initialize the PSD device when it leaves the Manufacturing
phase. This process will initialize the indicia application along with all its related data
completely as defined by ASCOM Manufacturing. The new application is loaded into the PSD
as part of the functions related to this service.
ASCOM Manufacturing, in the initialization phase of the PSD, uses certain special diagnostic
applications and other initialization applications in order to initialize various data objects and
finally to load the indicia application which provides the control for use of the PSD in the
field.
Data to be initialized includes the current date, time and attributes which identify and describe
the specific device.
4.3.2 Customer Specific Initialization
This service includes functions performed by ASCOM Remote Control in the field in order to
configure the PSD for the use with a specific customer.
This includes loading of attributes identifying and describing the specific customer. It also
includes the setting of values for parameters, which are specific for the customer and are
recognized by the indicia application in operation (e.g. limits for new funds).
4.3.3 Funds Download
TMS may access the PSD in the field through the KMS functional entity for downloading of
new funds. The communications with the PSD and the related exchange of TMS data is
accommodated via the cryptographically secured messaging mechanism specified in section
4.3.7.
TMS carries out the following operations as part of the funds downloading operation:
• receives a request for download of new funds and grants new funds after having performed
suitable checks and
• performs a check of the value of postal funds in the PSD allowing TMS to compare it with
available information for correctness (“device audit”);
• reads various values and parameters of the PSD configuration, the Indicia application
configuration and the customer attributes;
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• may modify the PSD’s date-and-time;
• releases the PSD for further use.
The PSD tracks the remaining amount of available funds and the total amount of funds used
for indicia creation14
.
A PSD internal Watchdog timer is used to automatically inhibit further indicia creations until
proper audit is done.
The TMS provides the accounting services necessary to support USPS funds management
requirements.
4.3.4 Indicia Generation
The Customer may generate indicia using the available funds [USPS00]. The creation of
indicia decreases the available amount of funds while it increases the overall sum of funds
used. Any other change of the funds is restricted to TMS.
A precondition for indicia generation is that the PSD indicia application function is not
disabled because of an overdue audit (see section 4.3.3).
4.3.5 Log Extraction
ASCOM Remote Control may extract Statistics and Records from PSDs in the field for
diagnostic purposes, while ASCOM Manufacturing may extract this data as part of the Return
procedures.
4.3.6 Information
The PSD provides service functions to access various information available in the PSD. This
information is generally not regarded as confidential. The respective service commands may
be accessed therefore without the need of a preceding authentication.
Information available includes:
• the current amount of postal funds;
• the value of various application relevant parameters (as applicable limits);
• various attributes identifying and describing the specific customer and the device;
• diagnostics and status information about the PSD device.
4.3.7 Management of Cryptographic Services
ASCOM Manufacturing and ASCOM Remote Control may query and set various elements of
the PSD’s cryptographic material (see section 4.2.6) within the context of the key management
concept described in section 5.
Available functions for ASCOM Manufacturing in the Initialization phase are:
14
These values are referred to conceptually as “descending register” and “ascending register”, see [USPS00].
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• initiate the generation of a PSD authentication key pair in a PSD and get the public key
component for certification;
• initiate the generation of the PIN keys used to decrypt the securely transmitted PIN
received for Customer authentication to the PSD,
• set and verify cryptographic parameters and certificates.
Available functions for ASCOM Remote Control in the field are:
• initiate the generation of a Indicia key pair in a PSD and get the public key component
from the PSD for certification;
• re-keying of a PSD (e.g. initiate the PSD internal generation of a new Indicia key pair);
• PSD log extraction.
The data exchanged for the purpose of the management of cryptographic services is secured
using an “authenticated Diffie-Hellman channel” with data integrity protection and symmetric
encryption.
The communications protocol used to establish the secure channel provides the following
security features:
• replay protection by using random numbers as time variant parameters;
• establishment of shared secret session keys between the two communicating entities by
Diffie-Hellman technique;
• mutual control of the shared secret keys;
• forward secrecy for the shared secret session keys (a compromised key does not put at risk
future session keys);
• authentication of the communicating parties by the use of digital signatures and
certificates;
• encryption and integrity protection through use of symmetric techniques;
• independent cryptographic keys for encryption and integrity protection.
4.3.8 Customer Authentication
The PSD is a single-user device that uses identity-based methods to authenticate its user. The
Customer is allowed to use the PSD to produce indicia that consumes the available postal
funds in the PSD. In order to do so, he has to perform a “login” into the PSD by presenting a
PIN to identify himself.
The Customer is authenticated using a PIN based mechanism. The PIN is set to a unique PSD
individual value in the Manufacturing phase. This value is made known to the customer using
a communication path different from the shipping of the PSD itself. The customer is
empowered to change the PIN when he uses the PSD the first time.
The PSD expects the customer identity PIN to be entered each time after powering up and
before using the customer role. The PSD also expects the PIN authentication procedure to be
performed again each time the synchronization at the serial interface between the PSD and the
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host system is lost. This event indicates to the PSD that it might have been moved to a
different host system.
PIN authentication must be performed, before any indicia application function (indicia
generation and TMS activities) is allowed by the PSD.
Whenever a specific consecutive number of authentication failures has occurred the PIN
authentication function is locked, which effectively prevents the access to the indicia
generation. ASCOM Remote Control may reset the PIN to its initial value.
At first power-up of an initialized PSD, the customer enters the PIN through a keypad on the
host/base. The host/base then encrypts the PIN and transfers it to the PSD. The Customer is
not forced to re-enter the PIN at each power-up since this is the only entity that accesses the
module through this interface, in the field.
The PIN is protected by encryption prior to transmission from the host/base to the PSD by
symmetric keys. This applies to both the regular entry of the current PIN and to a PIN change.
The PIN is never communicated in the clear.
The PIN keys are triple DES keys generated by the PSD and used for secure transmission of
the Customer PIN. This process is initially performed in the initialization phase.
4.4 Enabling/Disabling the Postal Security Device (PSD)
Based on several pre-defined security criteria (e.g. time, postal funds or piece count based
limits) operations of a PSD in the field may be enabled/disabled remotely by TMS and
ASCOM Remote Control, respectively, in case one or more of the criteria are met.
The battery-backed RAM contains all the security-critical data elements such as the
certificates and keys. When the electronic tamper response mechanism is activated, all the
security-critical data elements in RAM are destroyed (zeroed) thus making the PSD
inoperative.
5 Key Management
The following cryptographic elements are stored in a PSD:
• ASCOM Root CA certificate,
• ASCOM (Factory Region) Regional CA certificate (temporarily),
• ASCOM Regional CA certificate,
• ASCOM Manufacturing certificate (temporarily),
• ASCOM Remote Control certificate (temporarily),
• PSD Authentication certificate and the corresponding private key,
• Indicia certificate and private key,
• User PIN Keys,
• TMS keys,
• Ephemeral Diffie-Hellman keys (temporarily).
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Table 10: Cryptographic elements stored in the PSD
Cryptographic
element
Generation Initialization in
PSD
Usage by PSD Replacement in PSD
ASCOM Root CA
certificate
Generated by
ASCOM Root
CA
Manufacturing/
initialization phase
Verification of Regional
CA certificates.
Verification of signatures
on PSD application
binaries.
As part of re-keying
When Return application
is loaded
Ephemeral Diffie-
Hellman key pairs
Generated by
PSD
Initialization/Autho
rization/Operation
phase
(Temporarily)
Creation of session keys
for secure communication
with the KMS.
Whenever a secure
communication session is
created
ASCOM (Factory
Region) Regional
CA certificate
Issued by
ASCOM Root
CA
Manufacturing/
initialization phase
(Temporarily)
Verification of
Manufacturing Certs
(only Factory Region).
As part of Authorization
When Return application
is loaded
ASCOM
Manufacturing
certificate
Issued by
ASCOM
(Factory
Region)
Regional CA
Manufacturing/
initialization phase
(Temporarily)
Verification of ASCOM
Manufacturing and signed
data of message
exchanges with KMS.
As part of Authorization
When Return application
is loaded
ASCOM Regional
CA certificate
Issued by
ASCOM Root
CA
Authorization phase Verification of Remote
Control Certs.
As part of re-keying
When Return application
is loaded
PSD Authentication
key pair
Generated by
PSD
Initialization phase Private key signs data of
message exchanges with
regional KMS
As part of re-keying
When return application is
loaded
ASCOM Remote
Control certificate
Issued by
ASCOM
Regional CA
Authorization phase (Temporarily)
Verification of ASCOM
Remote Control and
signed data of message
exchanges with KMS.
As part of re-keying
Indicia key pair Generated by
PSD
Authorization phase Private key signs indicia
data
As part of re-keying
When Return application
is loaded
TMS keys Agreed by
PSD and TMS
Operation phase Provide mutual
authentication of TMS
and PSDs and protection
of data integrity and
confidentiality
As part of every postal
funds download operation
When Return application
is loaded
User PIN Keys Initially
Generated by
PSD
Operation phase Logon to PSD When user enters his/her
own PIN
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5.1 ASCOM Root CA certificate
The ASCOM Root CA certificate is loaded into each PSD during the Manufacturing/
Initialization phase.
The ASCOM Root CA certificate is self-signed. It contains a hash of the next public key and
the associated cryptographic domain parameters.
The security of a subsequent replacement of the ASCOM Root CA Certificate (whether
accomplished remotely, in the field, or as part of the return re-manufacturing process) is based
on the data origin authentication and integrity protection provided by the hash value (being
part of the signed data) stored in the previous version of the ASCOM Root CA certificate.
The ASCOM Root CA private key is applied to issue ASCOM Regional CA certificates and to
sign PSD application binaries.
The PSD uses the ASCOM Root CA certificate to verify subsequent ASCOM Regional CA
certificates and to check the signature on application binaries to be loaded.
The first time an application is run it is verified against this signature, then a CRC is
calculated/stored and all subsequent startups of the application verify this CRC.
5.2 Ephemeral Diffie-Hellman Key Pair
The Diffie-Hellman key pairs are initially created by the PSD during the Manufacturing/
Initialization phase. These keys are used to establish shared secrets for authenticated Diffie-
Hellman communication sessions with the KMS for which, data integrity and confidentiality
are protected, see section 4.3.7.
5.3 ASCOM (Factory Region) Regional CA certificate
The ASCOM (Factory Region) Regional CA certificate is loaded into each PSD during the
Manufacturing/Initialization phase.
The ASCOM (Factory Region) Regional CA certificate is issued by the ASCOM Root CA.
The ASCOM (Factory Region) Regional CA private key is used to issue the following
certificates:
• ASCOM Manufacturing certificates;
• PSD Authentication certificates.
The PSD uses the ASCOM (Factory Region) Regional CA certificate to verify the ASCOM
Manufacturing certificate and thus the corresponding role.
The ASCOM Regional CA certificate is only temporarily stored in the PSD and is replaced
during the Authorization phase by the ASCOM Regional CA certificate when the PSD is sent
to a destination in the field.
5.4 ASCOM Manufacturing certificate
The ASCOM Manufacturing certificate is loaded into each PSD during the Manufacturing/
Initialization phase.
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The ASCOM Manufacturing certificate is issued by the ASCOM (Factory Region) Regional
CA.
The ASCOM Manufacturing private key is used to sign messages sent by ASCOM
Manufacturing to the PSD. The PSD uses the ASCOM Manufacturing certificate to verify the
ASCOM Manufacturing role and any signed messages sent by the entity. The ASCOM
Manufacturing certificate is only temporarily stored in the PSD and is replaced during the
Authorization phase by the Remote Control certificate when the PSD is sent to a destination in
the field.
5.5 ASCOM Regional CA certificate
The ASCOM Regional CA certificate is loaded into each PSD during the Authorization
phase15
.
The ASCOM Regional CA certificate is issued by the ASCOM Root CA.
The ASCOM Regional CA private key is used to issue the following certificates:
• ASCOM Remote Control certificates (or ASCOM Manufacturing certificates for the
Factory Region);
• PSD Authentication certificates.
The PSD uses the ASCOM Regional CA certificate to verify ASCOM Remote Control
certificate and thus the corresponding role.
In the field, ASCOM Remote Control may initialize a replacement of the ASCOM Regional
CA certificate in a specific PSD as part of a re-keying operation. This operation is integrated
in an authenticated Diffie-Hellman communication session for which, in addition, data
integrity and confidentiality are protected, see section 4.3.7.
The ASCOM Regional CA certificate contains a Region Code that controls when a new
regional certificate can replace an existing regional certificate in a PSD.
5.5.1 Region Codes
A Region Change procedure is used to reconfigure a PSD when it moves from one region to
another.
Each ASCOM Regional CA certificate will contain two region codes, the "Active Region
Code" and the "Prior Region Code". These region codes act as constraints on the certificate
change process to provide the ability to configure a PSD to its regional certificate hierarchy,
reconfigure a returned PSD for ASCOM manufacturing, and not allow a regional KMS to
reconfigure a PSD for a different region, cf. section 4.1.2.
5.6 PSD Authentication Key Pair
The PSD Authentication key pair is generated by the PSD itself. This process is performed
during manufacture of a PSD.
15
The ASCOM Regional CA certificate replaces the ASCOM Manufacturing certificate already stored in each
PSD.
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The public key is extracted by ASCOM Manufacturing and transferred to the ASCOM
Regional CA (of the Factory Region) for certification.
The PSD Authentication private key is used to sign responses by a PSD to ASCOM
Manufacturing and Remote Control messages.
In the field, ASCOM Remote Control may initialize a replacement of the PSD Authentication
key pair as part of a re-keying operation. This is done by first instructing the PSD to generate a
new key pair. As a result ASCOM Remote Control receives the public key part and transfers it
to the ASCOM Regional CA for certification. After receiving the certified public key back,
ASCOM Remote Control will instruct the PSD to switch from the old key to the new one,
which will be used from then on to authenticate the PSD to the regional KMS. This operation
is integrated in an authenticated Diffie-Hellman communication session for which, in addition,
data integrity and confidentiality are protected.
5.7 ASCOM Remote Control certificate
The ASCOM Remote Control certificate is loaded into each PSD during the Authorization
phase.
The ASCOM Remote Control certificate is issued by the ASCOM Regional CA.
The ASCOM Remote Control private key is used to sign messages sent by ASCOM Remote
Control to the PSD. The PSD uses the ASCOM Remote Control certificate to verify the
ASCOM Remote Control role and any signed messages sent by the entity.
The ASCOM Remote Control certificate is only temporarily stored in the PSD. In the field,
ASCOM Remote Control may initialize a replacement of the certificate as part of a re-keying
operation. This operation is integrated in an authenticated Diffie-Hellman communication
session for which, in addition, data integrity and confidentiality are protected, see section
4.3.7.
5.8 Indicia Key Pair
The Indicia key pair is generated by the PSD itself. This process is performed in the field
during the Authorization phase.
The public key is extracted by ASCOM Remote Control and transferred to USPS IBIP key
management infrastructure for certification.
The Indicia private key is used to sign indicia data.
In the field, ASCOM Remote Control may initialize a replacement of the Indicia key pair (re-
keying). This is done by first instructing the PSD to generate a new Indicia key pair. As a
result ASCOM Remote Control receives the public key part and transfers it the same way as in
the initialization phase to the USPS IBIP key management infrastructure for certification.
After receiving the certified public key back, ASCOM Remote Control will instruct the PSD
to switch from the old Indicia key to the new one, which will be used from then on for indicia
generation. This operation is integrated in an authenticated Diffie-Hellman communication
session for which, in addition, data integrity and confidentiality are protected.
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5.9 TMS Keys
The TMS keys are symmetric keys used to mutually authenticate TMS and PSDs and to
protect the integrity of the data exchange during a postal funds download operation.
The TMS keys are session keys agreed upon by a specific PSD and TMS as part of every PSD
reset operation.
The TMS related data exchange is embedded in an authenticated Diffie-Hellman
communication session for which data integrity and confidentiality are protected.
5.10 User PIN Keys
The generation of the PSD specific initial PINs takes place during the PSD initialization step
on Ascom's premises. The PSD itself internally generates its initial PIN using the ANSI
X9.17 PRNG. After having generated the random bits followed by some formatting the PSD
outputs the initial PIN to the Ascom KMS, which stores the value in a database.
5.11 Random Number Generation
The PSD uses a ‘true’ random number generator to seed its FIPS-approved ANSI X9.17
pseudo random number generator. The output of this PRNG is used for key generation by the
PSD.
6 IBI-Lite Indicia
The PSD may also produce USPS IBI-Lite indicia. The indicia is comprised of postage
information and using the existing “TMS login ID key” to encrypt the 17-byte IBI Lite data,
then appending the triple DES encrypted data results to the IBI data to provide authenticity of
the IBI data.
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7 Annexes
7.1 References
[FIPS94] Federal Information Processing Standards Publication 140-1: Security
Requirements for Cryptographic Module, 1994.
[USPS00] United States Postal Service (USPS): Information-Based Indicia Program
(IBIP) : Performance criteria for information-based indicia and security
architecture for IBI postage metering systems. February 23, 2000 – Draft
7.2 Acronyms
CA Certification Authority
DES Data Encryption Standard
DSA Digital Signature Algorithm
FIPS PUB Federal Information Processing Standard Publication
IBI Information Based Indicia
IBIP Indicia Based Information Program
PCB Printed Circuit Board
PIN Personal Identification Number
PSD Postal Security Device
TMS TeleMeter Setting System
TLE Known as the Halser PostLink (postage meter)
MATS USPS document that maps postage meter vendor products.
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Figure 3: Neopost Organization