Non-Proprietary FIPS 140-2 Security Policy
Google LLC
Non-Volatile Memory express (NVMe) Data
Path Security Cluster (DPSC) Module
Hardware version: 2.3.1
Date: March 29, 2022
Prepared By:
2400 Research Blvd, Suite 395
Rockville, MD 20850
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Introduction
Federal Information Processing Standards Publication 140-2 — Security Requirements for Cryptographic
Modules specifies requirements for cryptographic modules to be deployed in a Sensitive but Unclassified
environment. The National Institute of Standards and Technology (NIST) and Canadian Centre for Cyber
Security (CCCS) Cryptographic Module Validation Program (CMVP) run the FIPS 140 program. NVLAP
accredits independent testing labs to perform FIPS 140-2 testing; the CMVP validates modules meeting
FIPS 140-2 validation requirements. Validated is the term given to a module that is documented and
tested against the FIPS 140-2 criteria.
More information is available on the CMVP website at:
http://csrc.nist.gov/groups/STM/cmvp/index.html
About this Document
This non-proprietary Cryptographic Module Security Policy for the NVMe DPSC Module from Google LLC.
provides an overview of the product and a high-level description of how it meets the overall Level 1
security requirements of FIPS 140-2.
The NVMe DPSC Module may also be referred to as “NMVe DPSC” or the “module” in this document.
Disclaimer
The contents of this document are subject to revision without notice due to continued progress in
methodology, design, and manufacturing. Google LLC. shall have no liability for any error or damages of
any kind resulting from the use of this document.
Notices
This document may be freely reproduced and distributed in its entirety without modification.
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Table of Contents
Introduction 2
Disclaimer 2
Notices 2
1. Introduction 5
1.1 Scope 5
1.2 Overview 5
2. Security Level 5
3. Cryptographic Module Specification 6
3.1 Cryptographic Boundary 6
4. Cryptographic Module Ports and Interfaces 7
5. Roles, Services and Authentication 7
5.1 Roles 7
5.2 Services 7
5.3 Authentication 8
6. Physical Security 8
7. Operational Environment 8
8. Cryptographic Algorithms and Key Management 9
8.1 Cryptographic Algorithms 9
8.2 Cryptographic Key Management 9
8.3 Key Generation 9
8.4 Key Storage and Zeroization 9
9. Self-tests 10
9.1 Power-On Self-Tests 10
9.2 Conditional Self-Tests 10
9.3 Critical Function Tests 11
10. Mitigation of Other Attacks 11
11. Crypto Officer and User Guidance 11
12. Glossary 12
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List of Tables
Table 1 - Security Level .................................................................................................................................5
Table 2 - Physical Port and Logical Interface Mapping .................................................................................7
Table 3 - Approved Services and Role allocation..........................................................................................8
Table 4 - NVMe DPSC Approved Algorithms.................................................................................................9
Table 5 - Approved Keys and CSPs................................................................................................................9
Table 6 - Power-On Self-Tests.....................................................................................................................10
Table 7 - Conditional Self-Tests...................................................................................................................10
Table 8 - Glossary of Terms.........................................................................................................................12
List of Figures
Figure 1 - NVMe DPSC Block Diagram...........................................................................................................6
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1. Introduction
1.1 Scope
This document describes the cryptographic module security policy for the Google LLC. Non-Volatile
Memory express (NVMe) Data Path Security Cluster (DPSC) Module (Hardware Version: 2.3) (also referred
to as the “module” hereafter). It contains a specification of the security rules, under which the
cryptographic module operates, including the security rules derived from the requirements of the FIPS
140-2 standard.
1.2 Overview
The NVMe DPSC Module consists of a sub-chip IP Block in the ARM Cortex-A53 based Google IN762
System-on-a-chip (SoC). The sub-chip module provides a virtual NVMe (vNMVe) block device to host
hypervisor platforms and guest virtual machines (VMs). The NVMe DPSC consists of four (4) identical XTS-
AES Encrypt and four (4) identical XTS-AES Decrypt engines, a keycache SRAM and a key cache arbiter.
2. Security Level
The following table lists the level of validation for each area in FIPS 140-2:
FIPS 140-2 Section Title Validation Level
Cryptographic Module Specification 1
Cryptographic Module Ports and Interfaces 1
Roles, Services, and Authentication 1
Finite State Model 1
Physical Security 1
Operational Environment N/A
Cryptographic Key Management 1
Electromagnetic Interference / Electromagnetic Compatibility 1
Self-Tests 1
Design Assurance 1
Mitigation of Other Attacks N/A
Overall Level 1
Table 1 - Security Level
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3. Cryptographic Module Specification
3.1 Cryptographic Boundary
The physical boundary of the module is the single-chip physical embodiment of the IN762 SoC. The
module’s logical boundary is the hardware-based functionality contained within the NVMe DPSC IP Block
at the sub-chip level. The module only supports a single mode of operation where only Approved
cryptographic functions and services are available. The cryptographic boundary of the module and the
relationship among the various internal components of the module are depicted in Figure 1 below.
Figure 1 - NVMe DPSC Block Diagram
The module consists of the NVMe DPSC, which is an integral component of the NVMe Protocol Engine in
the IN762 SoC. The NVMe Protocol Engine provides a means to allow the host OS to communicate with
its storage through a standard PCIe-based NVMe/SSD driver while allowing the operator to provision that
storage either locally or across the network.
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NVMe DPSC provides XTS encryption and decryption of data written into functional blocks before being
offloaded to another subsystem via the NIC Management Fabric (NMF), which is connected via an AMBA1
on-chip system bus. DPSC includes 4 identical XTS-AES 256 decrypt engines, 4 identical XTS-AES 256
encrypt engines, key cache arbiter and key cache SRAM which is zeroized on reset. The data interfaces
exposed to the NVMe Protocol Layer (NPI) within the NVMe Protocol Initiator (NPI) are read and write
DMA interfaces. XTS keys are written to the module’s SRAM via Control/Status Register (CSR) writes from
the Integrated Management Complex (IMC) located outside of the module boundary. On-demand self-
tests may be initiated from the NPI using an on-demand self-test trigger over a wire interface.
4. Cryptographic Module Ports and Interfaces
The module provides the following number of physical and logical interfaces to the device, and the
physical interfaces provided by the module are mapped to the FIPS 140-2 defined logical interfaces: data
input, data output, control input, status output, and power. The logical interfaces and their mapping are
described in the following table:
FIPS 140-2 Interface Module Ports Description
Data Input WrDMA0, WrDMA1 Write DMA interfaces
Control/Status Register (CSR) Key cache writes
Data Output RdDMA0, RdDMA1 Read DMA interfaces
Control Input
Wire interface On-demand self-test trigger
Control/Status Register (CSR) Key cache writes
Status Output
Wire interface On-demand self-test status bit
Control/Status Register Status output
Power Input Physical power connector Provides power to the module
Table 2 - Physical Port and Logical Interface Mapping
5. Roles, Services and Authentication
5.1 Roles
The module meets all FIPS 140-2 level 1 requirements for Roles and Services, implementing both User and
Crypto Officer roles. The module does not allow concurrent operators. The User and Crypto Officer roles
are implicitly assumed by the entity accessing services implemented by the module. No further
authentication is required. The Crypto Officer is responsible to set the key for the cipher operation.
5.2 Services
The module provides only Approved services which utilize algorithms listed in Table 5:
Service Roles CSP CSP Access
User CO R = Read
W = Write
X = Execute
Supply an NVMe Protocol Data Unit (PDU) for
encryption
✔ ✔ Key1 and
Key2
R, W, X
Supply an NVMe PDU for decryption ✔ ✔ Key1 and
Key2
R, W, X
1
ARM Microcontroller Bus Architecture
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On-demand Self-Test (Self-Test is executed
automatically when device is booted or
restarted on-demand by using the self-test
trigger from external software)
✔ ✔ N/A N/A
Initialization ✔ ✔ N/A N/A
Zeroization ✔ ✔ Key1 and
Key2
W
Status Output ✔ ✔ N/A N/A
Table 3 - Approved Services and Role allocation
5.3 Authentication
There is no operator authentication; assumption of role is implicit by the used service(s). The User and
CO roles have access to all module services; there is no separation of role access.
6. Physical Security
NVMe DPSC is a sub-chip module implemented as part of the IN762 SoC, which is the physical boundary
of the sub-chip module. The IN762 SoC is a single chip with a production grade enclosure and hence
conforms to the Level 1 requirements for physical security.
7. Operational Environment
The module is a sub-chip cryptographic subsystem implemented within a single-chip hardware
embodiment. No firmware is implemented by the module.
The module is tested in the following single-chip operational environment:
• Google IN762 SoC B0
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8. Cryptographic Algorithms and Key Management
8.1 Cryptographic Algorithms
The module implements the following approved algorithms in hardware:
Data Path Security Cluster (DPSC) AES Engine version 2.3.1 Algorithm Implementations
CAVP Cert # Algorithm Sizes Standard Mode/Method Use
A1188
AES 256-bits SP 800-38A ECB2
Encryption,
Decryption
XTS3
256-bits SP 800-38E XTS Encryption,
Decryption
Table 4 - NVMe DPSC Approved Algorithms
8.2 Cryptographic Key Management
The module supports the following CSPs listed below in Table 5. The CSP access policy is denoted in
Table 3 above.
Keys and
CSPs
Description Algorithm
and Key Size
Generation Input / Output
Method
Storage Zeroization
Key1 Bulk
encryption
Key
256-bit value N/A. Provided
by calling
device
Input via direct CSR
interface. Never Exits
the module
Key cache
SRAM
Zeroized on
reset
Key2 Tweak Key 256-bit value N/A. Provided
by calling
device
Input via direct CSR
interface. Never Exits
the module
Key cache
SRAM
Zeroized on
reset
Table 5 - Approved Keys and CSPs
8.3 Key Generation
The module does not provide any key generation service or perform key generation for any of its Approved
algorithms. The caller provides the keys for encryption and/or decryption. Keys are stored in hardware
registers (write-only by software) by the Crypto Officer or User. Once the keys are written to the hardware
registers, they are not readable from outside the module.
The cryptographic module does not provide any asymmetrical algorithms or key establishment methods.
8.4 Key Storage and Zeroization
All keys and CSPs are stored in on-chip key cache SRAM (i.e. static registers). The key cache is write-only
and cannot be read from outside of the module. When the operator performs a reset of the IN762 SoC,
it will zeroize all CSPs contained within the module.
2
Crypto Engine only utilizes AES XTS. AES ECB is not callable in NVMe. It tested under ACVTS to demonstrate the
forward cipher function as required in the CAVP FAQ.
3
AES-XTS implementation is used for storage purposes only.
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The key cache logic on reset will auto-initialize the on-chip SRAM and key valid bits. The key cache is
initialized with all zeroes, and the key valid bits will be cleared to indicate that the key registers are invalid.
9. Self-tests
FIPS 140-2 requires self-tests to ensure the correctness of the cryptographic functionality at start-up.
Some functions require conditional tests during normal operation of the module.
If any of the tests fail, the module will return an error code and transition to an error state where no
functions can be executed. An operator can attempt to reset the state by cycling the power. However, the
repeated failure of a self-test may require the module to be replaced.
9.1 Power-On Self-Tests
Power-on self-tests are run upon the initialization of the module and do not require operator intervention
to run. If any of the tests fail, the module will not initialize, and any output of the XTS engines will be
driven to 0 (including the contents of the key cache). The module will enter an error state and no services
can be accessed by the operator.
The module implements the following power-on self-tests in the NVMe DPSC Module:
Type Test Description
Encrypt KAT XTS-AES 256 encryption (forward cipher function)
Decrypt KAT XTS-AES 256 decryption (inverse cipher function)
Table 6 - Power-On Self-Tests
The module performs all power-on self-tests automatically when it is initialized. Power-on self-tests must
pass before a User/Crypto Officer can perform services. The Power-on self-tests can be run on demand
by rebooting the module or by sending a self-test trigger signal bit from external software.
Note: The module is implemented entirely in hardware and is non-modifiable. Therefore, the integrity
test requirements do not apply.
9.2 Conditional Self-Tests
Conditional self-tests are run under specific conditions, such as during key generation. Though the
module does not perform key generation, per IG A.9, the module implements the following conditional
tests:
Type Test Description
Key Equality Check
(Encrypt)
Prior to use of an XTS key, the module verifies that Key1!=Key2 and the
key is present in the keycache.
Key Equality Check
(Decrypt)
Prior to use of an XTS key, the module verifies that Key1!=Key2 and the
key is present in the keycache.
Table 7 - Conditional Self-Tests
In the event that either of the above conditional tests fail, the output of the module will be driven to 0
for a given payload. However, the module will not enter an error state, rather the encryption or
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decryption request will fail, and the module will continue to process payload encryption and decryption
operations if the subsequent keys are valid and not equal.
9.3 Critical Function Tests
The module does not implement any specific critical function tests.
10. Mitigation of Other Attacks
No specific claims for this section.
11. Crypto Officer and User Guidance
No configuration of the module or installation steps are required from the operator. When the module
is powered on its power-up self-tests are executed without any operator intervention. The module
enters the Approved mode of operation automatically if the power-up self-tests complete successfully. If
any of self-tests fail during power-up, the module will transition to an error state. The status of the
module can be determined by the availability of the module. If the module is available, it has passed all
self-tests. If it is unavailable, it is in the error state or has not been properly initialized.
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12. Glossary
Term Description
AMBA ARM Microcontroller Bus Architecture
AES Advanced Encryption Standard
CAVP Cryptographic Algorithm Validation Program
CMVP Cryptographic Module Validation Program
CSP Critical Security Parameter
CSR Control/Status Register
CTR Counter
DMA Direct Memory Access
DPSC Data Path Security Cluster
ECB Electronic Codebook
FIPS Federal Information Processing Standards
IG Implementation Guidance
IMC Integrated Management Complex
KAT Known answer test
NMF NIC Management Fabric
NPI NVMe Protocol Initiator
NPL NVMe Protocol Layer
NVMe Non-volatile Memory express
PDU Protocol Data Unit
SoC System On Chip
SRAM Static Random Access Memory
SSD Solid State Drive
VM Virtual Machine
XTS XEX-based tweaked-codebook mode with ciphertext stealing
Table 8 - Glossary of Terms