Issue D – 06.28.2001
PROMAIL II (SIMPLY POSTAGE III)
SECURITY POLICY
Compiled By: W. HERRING
PRINCIPAL ELECTRONICS DESIGN ENGINEER
Issue D – 06.28.2001
TITLE: PROmail II SECURITY POLICY
ABSTRACT:
DATE ISSUE AMENDMENT DESCRIPTION
19.09.2000
26.09.2000
14.12.2000
28.06.2001
A
B
C
D
First Issue
Security level for ‘Self Tests’ (section 2) reduced
from 4 to 3. Rules in Section 5 modified to reflect
the existence and maintenance of 2 random
number generators – one for signatures and one
for private keys manufacture.
Updated as indicated. Copyright statement
changed on Infogard copy only.
Updated to reflect changes for PROmail II.
Originator: Date:
Authorised By: Date:
Issue D – 06.28.2001
CIRCULATION LIST
G. STEWARD
ORIGINATOR
Issue D – 06.28.2001
CONTENTS
1. Introduction...................................................................................................................1
1.1 Scope ................................................................................................................1
1.2 References.......................................................................................................1
1.3 Glossary of Names and Acronyms...............................................................2
2. Security Level ..............................................................................................................2
3. SMM Overview ............................................................................................................2
3.1 I/O Ports ............................................................................................................3
3.1.1 RS232 Port...........................................................................................3
3.1.2 USB port ...............................................................................................3
3.1.3 Scale Interface Port ............................................................................3
3.1.4 Print Mechanism Control Port ...........................................................3
3.1.5 Power Supply Port..............................................................................4
3.2 Life Cycle States..............................................................................................4
4. Roles and Services .....................................................................................................4
4.1 Neopost Administrator ....................................................................................5
4.1.1 Commission Service...........................................................................5
4.1.2 Tamper Arm Service...........................................................................6
4.1.3 Zeroise Private Key Service..............................................................6
4.1.4 Customer Enable Service..................................................................6
4.1.5 Postal Administration Service............................................................7
4.1.6 Customer Disable Service.................................................................7
4.2 Customer..........................................................................................................7
4.2.1 Postal Indicium Service......................................................................7
4.2.2 Postal Administration Request Service............................................8
4.2.3 General Postal Service.......................................................................8
5. Security Rules..............................................................................................................8
5.1 Authentication Rules.......................................................................................8
5.2 Key Generation ................................................................................................8
5.3 ConDITIONAL Self Test Rules......................................................................9
5.4 Power Up Self Test Rules..............................................................................9
5.5 SRDI storage.................................................................................................10
5.6 Tamper Response........................................................................................10
5.7 Software.........................................................................................................10
5.8 Status Indication...........................................................................................11
6. Definition of Security Related Data Items (SRDI) ...............................................12
7. Definition of SRDI Modes of Access .....................................................................13
Appendix 1.............................................................................................................................14
Appendix 2.............................................................................................................................15
Appendix 3.............................................................................................................................16
Appendix 4.............................................................................................................................17
Issue D – 20.12.2000
1
PROMAIL II SECURITY POLICY
1. INTRODUCTION
The PROmail II Secure Metering Module (SMM) is a unit embedded within the
Neopost PROmail II postal device. Integrated within the SMM are a
cryptographic processor, a real time clock, non-volatile memory, working
memory, and other components.
The postal services relate to the ultimate objective of the SMM, which is to
store postage funds belonging to a customer until they are needed by the
indicium dispensing system. The indicia are dispensed in the form of a
digitally signed image. This image is a unique bit pattern that can be
determined to have originated from a particular SMM at a particular point in
time.
The cryptographic functions are used to restrict access to postal services and
to authenticate where necessary postal service output.
1.1 SCOPE
This document contains a statement of the security rules under which
the SMM must operate. A number of these rules are wholly or partially
a consequence of the general environment in which the SMM is
intended to be placed and for this reason a brief description of this
environment is included.
1.2 REFERENCES
1.2.1 Information Based Indicia Program (IBIP), Performance Criteria
for Information Based Indicia and Security Architecture for IBI
Postage Metering Systems (PCIBISAIBIPMS), The United
States Postal Service (USPS), Draft August 19, 1998 (document
number unknown).
1.2.2 Security Requirements for Cryptographic Modules, Federal
Information Processing Standards Publication 140-1
1.2.3 Digital Signature Standard (DSS), Federal Information
Processing Standards Publication 186-2
1.2.4 Secure Hash Standard, Federal Information Processing
Standards Publication 180-1
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2
1.3 GLOSSARY OF NAMES AND ACRONYMS
SMM Secure Metering Module
SRDI Security Related Data Item
NVEM Non Volatile Electronic Memory
DSA Digital Signature Algorithm (Reference 3)
SHA-1 Secure Hash Algorithm (reference )
X DSA private key
Y DSA public key
P DSA common parameter P
Q DSA common parameter Q
G DSA common parameter G
I/O Input / Output
USPS United States Postal Service (reference 1)
2. SECURITY LEVEL
The SMM is a multiple chip, embedded, cryptographic module as defined in
reference (2). The SMM shall meet the overall requirements for Level 3
security as defined in reference (2). The following table shows the security
level requirement, as defined in reference (2), for each area of the SMM: -
Level
Cryptographic Module 3
Module Interfaces 3
Roles & Services 3
Finite State Machine 3
Physical Security 3
Software Security 3
Operating System Security N/A
Key Management 3
Cryptographic Algorithms 3
EMI/EMC 3
Self Tests 3
NA = not applicable
3. SMM OVERVIEW
The SMM consists of a processor cryptographic processor, a real time clock,
non-volatile memory, working memory, and other components that are
contained on a printed circuit board and enclosed within a tamper responsive
enclosure. This enclosure constitutes the cryptographic boundary.
The SMM contains dual redundant non-volatile electronic memories, which
enables both security-related data items and postal related data items to be
stored in duplicate if required. Duplicate storage is typically used to increase
MTBF.
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3
The SMM will input and output authenticated data that requires the services of
the cryptographic sub module and also non-authenticated data that has no
security implications and can pass freely across the cryptographic physical
boundary. The latter relates to non (cryptographic) security critical postal
functions. These functions are those required by the USPS as specified in
reference (1) and are postal critical.
3.1 I/O PORTS
A number of data channels extend outside the enclosure. These are
described in the following with respect to their use inside the SMM up
to the point at which they enter/exit the physical enclosure. However for
convenience of reference they are named according to their use
externally to the SMM:
3.1.1 RS232 Port
This is a serial communication port. Secure services within the
SMM can be activated by certain data sequences being applied
by a remote host computer such as a PC. An auxiliary device
such as a postal weigh scale can also be connected to this port.
3.1.2 USB port
This is a serial communication port. Secure services within the
SMM can be activated by certain data sequences being applied
by a remote host computer such as a PC.
3.1.3 Scale Interface Port
This is an analog interface port used to measure the output of
the scale load cell.
3.1.4 Print Mechanism Control Port
This is a data channel used only to apply controlling data to
various parts of the print mechanism in order to effect a
sequence whereby an indicia is printed onto a thermal label
media. These parts would include a stepper motor, a Thermal
Print head, Paper detection sensors, and a print head open
switch.
A Neopost Online PC can securely activate services within the
SMM by communication over either the RS232 or USBports.
Finally the customer can activate certain secure services such
as Postage Resetting within the SMM, that relate to the intended
function of a postage dispenser, by performing actions directly
on the connected PC using the PROmail Client application (user
interface)
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4
The port data channels are shared by secure and non-secure
procedures. The non-secure data activity is summarised in
Appendix 1.
3.1.5 Power Supply Port
This is an input only port, which provides for the supply of power
to the module firmware.
3.2 LIFE CYCLE STATES
The SMM assumes one of several main overall states during its life
cycle. These states are relevant to the accessibility of cryptographic
services. The states are: -
Uninitialised
• This is the default after manufacture. The SMM does not contain
the cryptographic parameters necessary to support interaction with
the Neopost Postal Administration Infrastructure. A factory
initialisation is required.
Initialised
• The SMM contains the cryptographic parameters necessary to
support interaction with the Neopost Postal Administration
Infrastructure but has not yet been registered with this
infrastructure.
Unfunded & Time_out Unfunded
• The SMM has been authorized and is capable of performing postal
functions, although cannot issue indicia. The SMM must be funded
before it can issue non-zero value indicia. The SMM will transition
to the Time_out Unfunded state if an audit transaction is not
performed before the watchdog timer expires.
Funded & Time_out Funded
• The SMM has been authorized and funded and will perform postal
functions including issuing indicia. The SMM will transition to the
Time_out Funded state if an audit transaction is not performed
before the watchdog timer expires.
Faulted
• The SMM has detected a security threat and will no longer provide
any services that could affect its SRDIs.
4. ROLES AND SERVICES
The SMM shall support two distinct operators. The SMM shall enforce
separation of entities using identity-based authentication and by restricting the
services available to each entity. Also some services are state dependent.
The allowable operators are the Neopost Administrator (or Crypto-officer) and
the Customer (User): -
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5
The Neopost Administrator incorporates both the Crypto officer and User roles
referred to in Reference 2.
For identity-based authentication the ID must first have been selected and
then all input data must be accompanied by a cryptographic signature, which
is derived from the input data, and from cryptographic parameters unique to
that entity. The cryptographic parameters used must already be present in the
SMM.
For the Administrator the cryptographic parameters must be input subsequent
to manufacture.
Where services have a state dependency then the SMM must be first placed
into an appropriate life cycle state. The entities are authenticated with respect
to state as shown in Appendix 1.
The relationship between SMM services and authenticated entities are
summarised in Appendix 2.
The relationship between SMM services and state is summarised in Appendix
3.
4.1 NEOPOST ADMINISTRATOR
The Neopost Administrator shall provide the services required to
commission and maintain the cryptographic parameters within the
SMM. These parameters are necessary for interaction with the
Neopost metering infrastructure.
The Neopost Administrator shall also provide those services necessary
to control, sustain, and monitor the postal operation of an SMM. These
shall require the identity of the operator to be provided and
authenticated.
The Neopost Administration services are:-
4.1.1 Initialisation Service
This service will carry out the following: -
• Input a non authenticated message containing a Neopost
X509 certificate which will include the public key (Y) and
DSA common parameters (PQG) corresponding to the
Administrator.
• Verify that the SMM is in the appropriate state for
acceptance of a ‘Commission’ service request (Appendix 1).
• Extract and store the PQGY values.
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6
• Generate and store a new SMM public (Y) key based upon
the newly input PQG and the SMM private key.
• Authenticate and output a message containing the SMM
public key (Y).
• Set the SMM state to ‘Commissioned’ so as to enable the
Administrator.
4.1.2 Tamper Arm Service
This service will carry out the following: -
• Tests tamper detection circuitry.
• If the tamper detection line goes high, zeroizes the memory
and sends out a tamper switch open detection message to
the test utility software.
• This provides the temporary tamper detection till the valid
private key is stored in the meter after the meter becomes
"Live" in factory. (The private key is regenerated after the
meter becomes "Live").
4.1.3 Zeroise Service
This service will carry out the following: -
• Input an non-authenticated message containing a request to
zero the current private key.
• Verify that the SMM is in the appropriate state for
acceptance of a ‘Commission’ service request (Appendix 3).
• Zero the private key SRDI.
4.1.4 Authorize Service
This service will: -
• Input an authenticated message containing postal critical
data items, plus an X509 Certificate containing a certified
SMM public key.
• Verify the authentication.
• Verify that the SMM is in the appropriate state for
acceptance of a ‘Customer Enable’ service request.
• Extract and store the postal data items.
• Extract and store the X509 SMM public key Certificate.
Issue D – 20.12.2000
7
• Set the SMM state ‘Customer Enabled’ thereby inhibiting
further access to the Manufacturing role services, but
enabling subsequent access to the remaining Administrator
services and certain postal critical Customer services.
4.1.5 Postal Administration Service
This service will: -
• Input an authenticated message containing a postal function
command and optionally accompanied by postal critical data
items required by the function.
• Verify the authentication.
• Verify that the SMM is in the appropriate state for
acceptance of a ‘Postal Admin’ service request.
• Perform the specified postal function using the optionally
provided postal data as required.
4.1.6 Withdraw Service
This service will: -
• Input an authenticated message requesting that the SMM set
itself to the ‘Customer Disabled’ state.
• Verify the authentication.
• Verify that the SMM is in the appropriate state for
acceptance of a ‘Customer Disable’ service request.
• Authenticate and output a message containing specific
postal critical data items required by Neopost before an SMM
is disabled.
• Set the SMM state ‘Customer Disabled’ thereby inhibiting
further access to the Administrator services and certain
postal critical customer role services.
4.2 CUSTOMER
These services are available to the Customer. They all require the
SMM to be in an appropriate state. The services are: -
4.2.1 Postal Indicium Service
Issue D – 20.12.2000
8
• This service requests printing of a postal indicium.
4.2.2 Postal Administration Request Service
• This service requests that the Neopost Administrator
authenticate to the meter and perform appropriate
authenticated operations.
4.2.3 General Postal Service
• This service requests status output.
5. SECURITY RULES
Rule statements are shown in italics. Other information is included for
background purposes only.
5.1 AUTHENTICATION RULES
5.1.1 The SMM shall provide two distinct operators, the Neopost
Administrator and the Customer.
5.1.2 The SMM shall provide identity-based authentication.
5.1.3 Signatures shall be 40 byte codes derived using the DSA
algorithm, as described in reference 3, using 1024 bit common
parameters (PQG). Random number generation employed by
the DSA shall be according to section 3.2 and 3.3 of reference
(3)
5.1.4 The cryptographic parameters (PQGY) for each identity
authenticated shall be independent and shall be stored in
predetermined fixed locations within the SMM. These shall be
able to be super-seeded by subsequent input values if required.
The parameters for the Administrator must be input after
manufacture.
5.1.5 The SMM shall authenticate exported data with 40 byte codes
derived using the DSA algorithm, as described in reference 3,
using 1024 bit common parameters (PQG). Random number
generation employed by the DSA shall be according to section
3.2 and 3.3 of reference (3)
5.2 KEY GENERATION
5.2.1 The SMM DSA Private key shall be generated according section
3.1 and 3.3 of reference (3).
5.2.2 The SMM DSA public key corresponding to its the private key
shall be calculated according to the relationship for derivation of
a DSA public key defined in reference 3.
Issue D – 20.12.2000
9
5.2.3 During private/public key pair generation data output from the
SMM shall be inhibited.
5.3 CONDITIONAL SELF TEST RULES
5.3.1 The SMM shall default to the ‘Uninitialised’ state if it does not
possess a valid private/public key pair. The validity of a key pair
shall be determined by a pair wise consistency check, i.e. the
calculation and verification of a signature. This check shall be
performed at the generation of each new key pair and at power
up.
5.3.2 For both the private key and signature random number
generators, the SMM shall perform the continuous random
number generator test, as defined in reference 2 for conditional
self tests, for every number generated and inhibit if its random
number generator fails to a constant value.
5.3.3 For both the private key and signature random number
generators, the SMM shall perform the continuous random
number generator test for as defined by reference (2). The SMM
shall inhibit all data output if the test fails.
For the signature random number generator, this will be
whenever the module is asked to initialise itself (i.e. at power up
or error reset). For the private key random number generator,
this will be when the module is requested to generate a private
key.
5.4 POWER UP SELF TEST RULES
5.4. 1 The SMM shall test the operation of Ram areas used for secure
operations at power up. The SMM shall inhibit if the test fails.
5.4.2 The SMM shall test the contents of it’s program memory area at
power up by calculating the 16 bit checksum (sum of bytes) of
the contents and comparing the result with a known answer. The
SMM shall inhibit if the test fails.
5.4.3 The SMM shall test the accessibility and validity of all SRDI
values in NVEM at power up. If a
ny are not accessible (i.e.
device failure) or contain erroneous data then the SMM shall
inhibit.
5.4.4 The SMM shall test the DSA algorithm at power up by
performing a known answer test for both signing and verification
using predetermined data embedded into the SMM firmware.
Testing of the secure hash algorithm (SHA-1) shall be inclusive
within the DSA test. The SMM shall inhibit if the test fails.
Issue D – 20.12.2000
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5.5 SRDI STORAGE
5.5.1 The SMM shall detect data corruption of the value held for any
particular SRDI by the incorporation of error detection data. The
probability of failing to detect an invalid SRDI by this method
shall be less than 1:50000.
The specified probability is also to be judged in the context that
even if a data error was not detected then the resultant
erroneous SRDI value should still be identified as erroneous via
the self tests (see Continuous and Power Up Self Test sections).
For example an erroneous public key would cause the pair wise
consistency check to fail.
5.5.2 The SMM shall establish the validity of any SRDI before
updating it with a new value. If erroneous the SMM shall abort
the service process that caused the update to be required.
A failure may be component failure.
5.5.3 Any access failure shall cause the SMM to inhibit. Exit from the
inhibit condition shall require the SMM to re check access to,
and the values of, all SRDI.
5.6 TAMPER RESPONSE
5.6.1 The SMM shall be a multi-chip embedded module and shall be
enclosed within a non-removable metal enclosure. The SMM
shall also contain micro-switches as part of its tamper-response
(zeroization) circuitry.
5.6.2 The DSA private key shall be erased should the SMM covers be
removed. At the same time the SMM shall enter an inhibited
state.
5.6.2 The DSA private key shall be erased if the temperature inside
the SMM covers exceeds 77 degrees Centigrade. At the same
time the SMM shall enter an inhibited state.
5.6.3 The private key shall not be exported under any circumstances.
5.7 SOFTWARE
5.7.1 The source for software contained in the f
irmware of the SMM
shall be written in C high level language. Exceptions to this shall
be the use of assembler level code to implement the following
time critical functions: -
-The multiply and modulus mathematical functions associated
with the DSA algorithm (reference 3).
Issue D – 20.12.2000
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5.8 STATUS INDICATION
5.8.1 The following ‘module not ready’ module states shall be
indicated: -
• Private key zeroed
• Private/Public key pair invalid (module not initialised)
• Tamper mechanism tampered
Indication will be via a unique text message output by the
module suitable for viewing on an alphanumeric display device.
The absence of one of these messages indicates that the
module is in a ‘ready’ state.
5.8.2 The following ‘module inhibited’ error conditions shall be
indicated: -
• DSA error
• RNG error
• SRDI access/data error
• Firmware / ram error
Indication will be via a unique text message output by the
module suitable for viewing on an alphanumeric display device.
The absence of one of these messages indicates that the
module does not have an error condition.
5.8.3 The module shall indicate the currently active role.
Indication will be via a unique text message output by the
module suitable for viewing on an alphanumeric display device.
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6. DEFINITION OF SECURITY RELATED DATA ITEMS (SRDI)
The following table describes each SRDI maintained by the SMM: -
SRDI NAME DESCRIPTION
DSA random number seed Current status of random number
Neopost Administration DSA public key Public key used for the verification of
authenticated messages input from the Neopost
Administration server.
Neopost Administration DSA common P Common cryptographic DSA parameter (P)
associated with the Neopost Administration
services.
Neopost Administration DSA common Q Common cryptographic DSA parameter (Q)
associated with the Neopost Administration
services.
Neopost Administration DSA common G Common cryptographic DSA parameter (G)
associated with the Neopost Administration
services.
Neopost Factory DSA public key Public key used for the verification of
authenticated messages input from the Neopost
Factory server.
Neopost Factory DSA common P Common cryptographic DSA parameter (P)
associated with the Neopost Factory services.
Neopost Factory DSA common Q Common cryptographic DSA parameter (Q)
associated with the Neopost Factory services.
Neopost Factory DSA common G Common cryptographic DSA parameter (G)
associated with the Neopost Factory services.
Neopost Factory services transaction
code
Neopost factory service transaction identifier
code. This is included in every input factory
service message and is incremented after each
factory service function so that each factory input
message cannot be re used.
SMM DSA private key The SMM private DSA key used to authenticate
messages and data output from the SMM.
SMM DSA public key DSA Public key of the SMM. Available to any
operator with a need to verify authenticated data
output by the SMM.
SMM life cycle state Indicates the SMM life cycle state.
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13
7. DEFINITION OF SRDI MODES OF ACCESS
The section describes how SRDI are accessed by the services that can be
activated by an operator. The modes of access are defined as follows: -
r The data item will be read for internal use.
e The data item will be read and exported.
w The data item will be updated directly from an imported value.
m The data item will be modified to a value created by an internal process.
z The data item will be zeroed.
s The data item will be initialised to a starting value created by an internal
process.
i The data item will be initialised to a benign value (typically zeroed).
The following table(s) summarises the relationship between all SRDI
maintained by the SMM and the services that access them: -
Service Name 8
SRDI Name 6
Tamper
Arm
Initialize
Zeroise
Private
Key
Auhtorize
Postal
Admin
Withdraw
Postal
Indicium
Admin
Request
General
Postal
Tamper
Self
Test
DSA random number seed s m m m
Neopost Administration DSA public key w r r r
Neopost Administration DSA common P w r r r r r r
Neopost Administration DSA common Q w r r r r r r
Neopost Administration DSA common G w r r r r r r
Neopost Factory DSA public key
Neopost Factory DSA common P
Neopost Factory DSA common Q
Neopost Factory DSA common G
Neopost Factory services transaction code
SMM DSA private key I s z r r z r
SMM DSA public key s r
SMM life cycle state m m r m r r
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APPENDIX 1
The following table summarises the services permitted by each of the SMM life cycle
states: -
STATE8
ENTITY6
UnInitialised Initialised Unfunded/
Funded
Withdrawn
Administration
Services v v v v
Neopost
Administrator Customer
Services
v
The service is not permitted unless specifically indicated: -
v = permitted
Issue D – 20.12.2000
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APPENDIX 2
The following table summarises the relationship between services and operators for
the SMM: -
NEOPOST ADMINISTRATOR
ENTITY 8
SERVICE 6
ADMINISTRATION
SERVICES
CUSTOMER
SERVICES
Tamper Arm v
Zeroise Private Key v
Initialize v
Authorize v
Postal Admin v
Withdraw v
Postal Indicium v
AdminRequest v
General Postal v
Service is not accessible to a particular entity unless specifically indicated:-
v = can be accessed
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APPENDIX 3
The following table summarises the legality of services according to the prevailing
life cycle state of an SMM: -
LIFE CYCLE STATE 4
SERVICE 6
UNINITIALISED
INITIALISED
UNFUNDED/FUNDED
WITHDRAWN
Tamper Arm v
Zeroise v v
Initialize v
Autorize v
Postal Admin v
Withdraw v
Postal Indicium v
AdminRequest v
General Postal v v v v
A service is not permitted for a particular state unless indicated: -
v = permitted
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APPENDIX 4
The following table summarises the SMM ports on which services are permitted to
be active: -
PORT8
SERVICE 6
RS232
PORT
USB PORT BUTTON/
LEDS
PORT
PRINT
MOTOR
DRIVE
PRINT
SENSORS
(PAPER
OUT/HEAD
OPEN)
TamperArm v v
Zeroise v v
Withdraw v v
Authorize v v
Postal Admin v v
Withdraw v v
Postal Indicium v
Admin Request v v
General Postal v v v
A service is not permitted via a port unless specifically indicated: -
v = permitted
EM
27.06.2001