RATS Working Group M. Richardson
Internet-Draft Sandelman Software Works
Intended status: Informational C. Wallace
Expires: May 6, 2021 Red Hound Software
W. Pan
Huawei Technologies
November 02, 2020
Use cases for Remote Attestation common encodings draft-richardson-rats-usecases-08Abstract
This document details mechanisms created for performing Remote Attestation that have been used in a number of industries. The document initially focuses on existing industry verticals, mapping terminology used in those specifications to the more abstract terminology used by the IETF RATS Working Group.
The document aspires to describe possible future use cases that would be enabled by common formats.
Status of This Memo
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 6, 2021.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
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Table of Contents1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Static attestations . . . . . . . . . . . . . . . . . . . 4
2.2. Session attestations . . . . . . . . . . . . . . . . . . 4
2.3. Statements . . . . . . . . . . . . . . . . . . . . . . . 4
2.4. Hardware Root Of Trust . . . . . . . . . . . . . . . . . 4
2.5. Template for Use cases . . . . . . . . . . . . . . . . . 5
3. Requirements Language . . . . . . . . . . . . . . . . . . . . 5
4. Overview of Sources of Use Cases . . . . . . . . . . . . . . 6
5. Use case summaries . . . . . . . . . . . . . . . . . . . . . 6
5.1. Device Capabilities/Firmware Attestation . . . . . . . . 6
5.1.1. Relying on an (third-party) Attestation Server . . . 7
5.1.2. Autonomous Relying Party . . . . . . . . . . . . . . 7
5.1.3. Proxy Root of Trust . . . . . . . . . . . . . . . . . 8
5.1.4. network scaling - small . . . . . . . . . . . . . . . 8
5.1.5. network scaling - medium . . . . . . . . . . . . . . 9
5.1.6. network scaling - large . . . . . . . . . . . . . . . 9
5.2. Hardware resiliency / watchdogs . . . . . . . . . . . . . 10
5.3. IETF TEEP WG use case . . . . . . . . . . . . . . . . . . 10
5.4. Confidential Machine Learning (ML) model . . . . . . . . 11
5.5. Critical infrastructure . . . . . . . . . . . . . . . . . 11
5.5.1. Computation characteristics . . . . . . . . . . . . . 12
5.6. Virtualized multi-tenant hosts . . . . . . . . . . . . . 13
5.7. Cryptographic Key Attestation . . . . . . . . . . . . . . 13
5.7.1. Device Type Attestation . . . . . . . . . . . . . . . 14
5.7.2. Key storage attestation . . . . . . . . . . . . . . . 14
5.7.3. End user authorization . . . . . . . . . . . . . . . 15
5.8. Geographic attestation . . . . . . . . . . . . . . . . . 15
5.8.1. I am here . . . . . . . . . . . . . . . . . . . . . . 16
5.8.2. I am near . . . . . . . . . . . . . . . . . . . . . . 16
5.8.3. You are here . . . . . . . . . . . . . . . . . . . . 16
5.9. Connectivity attestation . . . . . . . . . . . . . . . . 16
5.10. Component connectivity attestation . . . . . . . . . . . 17
5.11. Device provenance attestation . . . . . . . . . . . . . . 17
5.12. DNS privacy policy . . . . . . . . . . . . . . . . . . . 18
5.13. Safety Critical Systems . . . . . . . . . . . . . . . . . 19
5.14. Trusted Path Routing . . . . . . . . . . . . . . . . . . 19
6. Technology users for RATS. . . . . . . . . . . . . . . . . . 20
6.1. Trusted Computing Group Remove Integrity Verification
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(TCG-RIV) . . . . . . . . . . . . . . . . . . . . . . . . 20
6.2. Android Keystore system . . . . . . . . . . . . . . . . . 22
6.3. Fast IDentity Online (FIDO) Alliance . . . . . . . . . . 23
7. Examples of Existing Attestation Formats. . . . . . . . . . . 24
7.1. Android Keystore . . . . . . . . . . . . . . . . . . . . 24
7.1.1. TEE . . . . . . . . . . . . . . . . . . . . . . . . . 25
7.1.2. Secure Element . . . . . . . . . . . . . . . . . . . 37
7.2. Windows 10 TPM . . . . . . . . . . . . . . . . . . . . . 50
7.2.1. Attestation statement . . . . . . . . . . . . . . . . 52
7.3. Yubikey . . . . . . . . . . . . . . . . . . . . . . . . . 56
7.3.1. Yubikey 4 . . . . . . . . . . . . . . . . . . . . . . 56
7.3.2. Yubikey 5 . . . . . . . . . . . . . . . . . . . . . . 60
8. Privacy Considerations. . . . . . . . . . . . . . . . . . . . 64
9. Security Considerations . . . . . . . . . . . . . . . . . . . 64
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 64
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 64
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 64
12.1. Normative References . . . . . . . . . . . . . . . . . . 64
12.2. Informative References . . . . . . . . . . . . . . . . . 64
Appendix A. Changes . . . . . . . . . . . . . . . . . . . . . . 67 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 68
1. Introduction
The recently chartered IETF RATS WG intends to create a system of attestations that can be shared across a multitude of different users.This document exists as place to collect use cases for the common RATS technologies in support of the IETF RATS charter point 1. This document is not expected to be published as an RFC, but remain open as a working document. It could become an appendix to provide motivation for a protocol standards document.
End-user use cases that would either directly leverage RATS technology, or would serve to inform technology choices are welcome, however.
2. Terminology
Critical to dealing with and contrasting different technologies is to collect terms which are compatible, to distinguish those terms which are similar but used in different ways.This section will grow to include forward and external references to terms which have been seen. When terms need to be disambiguated they will be prefixed with their source, such as "TCG(claim)" or "FIDO(relying party)" Platform attestations generally come in two categories. This document will attempt to indicate for a particular attestation technology falls into this.
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Internet-Draft useful RATS November 2020 2.1. Static attestationsA static attestation says something about the platform on which the code is running.
2.2. Session attestations
A session attestation says something about how a session key used in a connection such as TLS connection was created. It is usually the result of evaluating attestations that are attached to the certificates used to create such a session.
2.3. Statements
The term "statement" is used as the generic term for the semantic content which is being attested to.
2.4. Hardware Root Of Trust
[SP800-155] offers the following definition for root of trust."Roots of Trust are components (software, hardware, or hybrid) and computing engines that constitute a set of unconditionally trusted functions. Reliable and trustworthy BIOS integrity measurement and reporting depend upon software agents; each software agent relies upon Roots of Trust, and the level of trustworthiness in each agent depends on its Roots of Trust. BIOS integrity measurement requires the coordination of a Measurement Agent to harvest measurements, a Storage Agent to protect the measurements from modification until they can be reported, and a Reporting Agent to reliably report the measurements. Each of these agents has a corresponding Root of Trust (Root of Trust for Measurement, etc.) These Roots of Trust must act in concert and build on each other to enable reliable and trustworthy measurement, reporting, and verification of BIOS integrity measurements."
SP800-155 uses the terms RoT for Reporting, Storage and Measurement, but not RoT for Verification - it uses "Verification Agent". Though it is assumed the verifier is trustworthy.
However, [tcgglossary] (page 9) includes a RoT for Verification (RTV) as well.
The TCG Glossary also offers a general definition for Root of Trust "A component that performs one or more security-specific functions, such as measurement, storage, reporting, verification, and/or update. It is trusted always to behave in the expected manner, because its misbehavior cannot be detected (such as by measurement) under normal operation. "
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[SP800-147B] defines RoT for Update (RoTU) and RoTU verification (RoTU-v).The TCG definition seems more concise than the NIST, but gets to the same point.
For the purpose of this documenet, a hardware root of trust refers to security functionality that is trusted to behave in the expected manner, because its misbehavior cannot be detected under normal operation and resists soft exploits by encapsulating the functionality in hardware.
2.5. Template for Use cases
Each use case will consist of a table with a number of constant fields, as illustrated below. The claim names will be loosely synchronized with the EAT draft. The role workflow (formerly "attestation type") will be described in the architecture draft. It will describe two classes of workflow: the passport type (Attestee sends evidence to Attester, receives signed statment, which is sent to relying party), or the background check type (Attestee sends measurements to Relying party, Relying Party checks with Attester).Use case name: Twelve Monkeys
Who will use it: Army of the Twelve Monkeys SDO
Attester: James Cole
Relying Party: Dr. Kathryn Reilly
Message Flow: Passport
Claims used as evidence: OEM Identity, Age Claim, Location Claim,
ptime Claim
Description: James Cole must convince Dr. Reilly he is from the
future, and not insane.
3. Requirements Language
This document is not a standards track document and does not make any normative protocol requirements using terminology described in [RFC2119].
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Internet-Draft useful RATS November 2020 4. Overview of Sources of Use CasesThe following specifications have been covered in this document:
o The Trusted Computing Group "Network Device Attestation Workflow" [I-D.fedorkow-rats-network-device-attestation]
o Android Keystore
o Fast Identity Online (FIDO) Alliance attestation,
This document will be expanded to include summaries from:
o Trusted Computing Group (TCG) Trusted Platform Module (TPM)/Trusted Software Stack (TSS)
o ARM "Platform Security Architecture" [I-D.tschofenig-rats-psa-token]
o Intel SGX attestation [intelsgx]
o Windows Defender System Guard attestation [windowsdefender]
o Windows Device Health Attestation [windowshealth]
o Azure Sphere Attestation [azureattestation]: https://azure.microsoft.com/enus/resources/azure-sphere-device- authentication-andattestation-service/en-us/
o IETF NEA WG [RFC5209]
Additional sources are welcome and requested.
5. Use case summaries
This section lists a series of cases where an attestation is done.
5.1. Device Capabilities/Firmware Attestation
This is a category of claimsUse case name: Device Identity
Who will use it: Network Operators
Attester: varies
Message Flow: varies Relying Party: varies
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Claims used as evidence: TBDDescription: Network operators want a trustworth report of identity and version of information of the hardware and software on the machines attached to their network. The process starts with some kind of Root of Trust that provides device identity and protected storage for measurements. The mechanism performs a series of measurements, and expresses this with an attestation as to the hardware and firmware/software which is running.
This is a general description for which there are many specific use cases, including [I-D.fedorkow-rats-network-device-attestation] section 1.2, "Software Inventory"
5.1.1. Relying on an (third-party) Attestation Server
Use case name: Third Party Attestation ServerWho will use it: Network Operators
Message Flow: background check
Attester: manufacturer of OS or hardware system
Relying Party: network access control systems
Claims used as evidence: TBD
Description: The measurements from a heterogenous network of devices are provided to device-specific attestation servers. The attestation servers know what the "golden" measurements are, and perform the appropriate evaluations, resulting in attestations that the relying parties can depend upon.
5.1.2. Autonomous Relying Party
Use case name: AutonomousWho will use it: network operators
Message Flow: passport
Attester: manufacturer of OS or hardware system
Relying Party: peer systems Claims used as evidence: TBD
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Description: The signed measurements are sent to a relying party which must validate them directly. They are not sent to a third party. (It may do so with the help of a signed list of golden values, or some other process). The relying party needs to validate the signed statements directly.This may occur because the network is not connected, or even because it can not be connected until the equipment is validated.
5.1.3. Proxy Root of Trust
Use case name: Proxy Root of TrustWho will use it: network operators
Message Flow: passport
Attester: manufacturer of OS or hardware system
Relying Party: peer systems
Claims used as evidence: TBD
Description: A variety of devices provide measurements via their Root of Trust. A proxy server collects these measurements, and (having applied a local policy) then creates a device agnostic attestation. The relying party can validate the claims in a standard format.
5.1.4. network scaling - small
Use case name: Network scaled - smallWho will use it: enterprises
Message Flow: background check
Attester: manufacturer of OS or hardware system
Relying Party: network equipment
Claims used as evidence: TBD
Description: An entire network of systems needs to be validated (such as all the desktops in an enterprise's building). The infrastructure is in the control of a single operator and is already trusted. The network can be partitioned so that machines that do not pass attestation can be quarantined. A 1:1 relationship between the device and the relying party can be used to maintain freshness of the attestation.
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Internet-Draft useful RATS November 2020 5.1.5. network scaling - mediumUse case name: Network scaled - medium
Who will use it: larger enterprises, including network operators
Message Flow: passport
Attester: manufacturer of OS or hardware system
Relying Party: network equipment
Claims used as evidence: TBD
Description: An entire network of systems needs to be validated: such as all the desktops in an enterprise's building, or all the routers at an ISP. The infrastructure is not necessarily trusted: it could be subverted, and it must also attest. The devices may be under a variety of operators, and may be mutually suspicious: each device may therefore need to process attestations from every other device. An NxM mesh of attestations may be untenable, but a system of N:1:M relationships can be setup via proxy attestations.
5.1.6. network scaling - large
Use case name: Network scaled - largeWho will use it: telco/LTE operators
Message Flow: passport
Attester: manufacturer of OS or hardware system
Relying Party: malware auditing systems
Claims used as evidence: TBD
Description: An entire network of systems need to be continuously attested. This could be all of the smartphones on an LTE network, or every desktop system in a worldwide enterprise. The network operator wishes to do this in order to maintain identities of connected devices more than to validate correct firmware, but both situations are reasonable.
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Internet-Draft useful RATS November 2020 5.2. Hardware resiliency / watchdogsUse case name: Hardware watchdog
Who will use it: individual system designers
Message Flow: passport
Attester: manufacturer of OS or hardware system
Relying Party: bootloader or service processor
Claims used as evidence: TBD
Description: One significant problem is malware that holds a device hostage and does not allow it to reboot to prevent updates to be applied. This is a significant problem, because it allows a fleet of devices to be held hostage for ransom. Within CyRes the TCG is defining hardware Attention Triggers that force a periodical reboot in hardware.
This can be implemented by forcing a reboot unless attestation to an Attestation Server succeeds within the period interval, and having a reboot do remediation by bringing a device into compliance, including installation of patches as needed.
This is unlike the previous section on Device Attestation in that the attestation comes from a network operator, as to the device's need to continue operating, and is evaluated by trusted firmware (the relying party), which resets a watchdog timer.
5.3. IETF TEEP WG use case
Use case name: TAM validationWho will use it: The TAM server
Message Flow: background check
Attester: Trusted Execution Environment (TEE)
Relying Party: end-application
Claims used as evidence: TBD
Description: The "Trusted Application Manager (TAM)" server wants to verify the state of a TEE, or applications in the TEE, of a device. The TEE attests to the TAM, which can then decide whether to install sensitive data in the TEE, or whether the TEE is out of compliance and the TAM needs to install updated code in the TEE to bring it back into compliance with the TAM's policy.
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Internet-Draft useful RATS November 2020 5.4. Confidential Machine Learning (ML) modelUse case name: Machine Learning protection
Who will use it: Machine Learning systems
Message Flow: TBD
Attester: hardware TEE
Relying Party: machine learning model owner
Claims used as evidence: TBD
Description: An example use case is where a device manufacturer wants to protect its intellectual property in terms of the ML model it developed and that runs in the devices that its customers purchased, and it wants to prevent attackers, potentially including the customer themselves, from seeing the details of the model. This works by having some protected environment (e.g., a hardware TEE) in the device attest to some manufacturer's service, which if attestation succeeds, then the manufacturer service releases the model, or a key to decrypt the model, to the requester. If a hardware TEE is involved, then this use case overlaps with the TEEP use case.
5.5. Critical infrastructure
Use case name: Critical InfrastructureWho will use it: devices
Message Flow: TBD
Attester: plant controller
Relying Party: actuator
Claims used as evidence: TBD
Description: When a protocol operation can affect some critical system, the device attached to the critical equipment wants some assurance that the requester has not been compromised. As such, attestation can be used to only accept commands from requesters that are within policy. Hardware attestation in particular, especially in conjunction with a TEE on the requester side, can provide protection against many types of malware.
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Internet-Draft useful RATS November 2020 5.5.1. Computation characteristicsUse case name: Shared Block Chain Computational claims
Who will use it: Consortia of Computation systems
Message Flow: TBD
Attester: computer system (physical or virtual)
Relying Party: other computer systems
Claims used as evidence: TBD
Description: A group of enterprises organized as a consortium seeks to deploy computing nodes as the basis of their shared blockchain system. Each member of the consortium must forward an equal number of computing nodes to participate in the P2P network of nodes that form the basis of the blockchain system. In order to prevent the various issues (e.g. concentration of hash power, anonymous mining nodes) found in other blockchain systems, each computing node must comply to a predefined allowable manifest of system hardware, software and firmware, as agreed to by the membership of the consortium. Thus, a given computing node must be able to report the (pre-boot) configuration of its system and be able to report at an y time the operational status of the various components that make-up its system.
The consortium seeks to have the following things attested: system configuration, group membership, and virtualization status.
This is a peer-to-peer protocol so each device in the consortium is a relying party. The attestation may be requested online by another entity within the consortium, but not by other parties. The attestation needs to be compact and interoperable and may be included in the blockchain itself at the completion of the consensus algorithm.
The attestation will need to start in a hardware RoT in order to validate if the system is running real hardware rather than running a virtual machine.
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Internet-Draft useful RATS November 2020 5.6. Virtualized multi-tenant hostsUse case name: Multi-tenant hosts
Who will use it: Virtual machine systems
Message Flow: TBD
Attester: virtual machine hypervisor
Relying Party: network operators
Claims used as evidence: TBD
Description: The host system will do verification as per 5.1.
The tenant virtual machines will do verification as per 5.1
The network operator wants to know if the system _as a whole_ is free of malware, but the network operator is not allowed to know who the tenants are.
This is contrasted to the Chassis + Line Cards case (To Be Defined: TBD).
Multiple Line Cards, but a small attestation system on the main card can combine things together. This is a kind of proxy.
5.7. Cryptographic Key Attestation
Use case name: Key AttestationWho will use it: network authentication systems
Message Flow: TBD
Attester: device platform
Relying Party: internet peers
Claims used as evidence: TBD
Description: The relying party wants to know how secure a private key that identifies an entity is. Unlike the network attestation, the relying party is not part of the network infrastructure, nor do they necessarily have a business relationship (such as ownership) over the end device.
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Internet-Draft useful RATS November 2020 5.7.1. Device Type AttestationUse case name: Device Type Attestation
Who will use it: mobile platforms
Message Flow: TBD
Attester: device platform
Relying Party: internet peers
Claims used as evidence: TBD
Description: This use case convinces the relying party of the characteristics of a device. For privacy reasons, it might not identify the actual device itself, but rather the class of device. The relying party can understand from either in-band (claims) or out-of-band (model numbers, which may be expressed as a claim) whether the device has trustworthy features such as a hardware TPM, software TPM via TEE, or software TPM without TEE. Other details such as the availability of finger-print readers or HDMI outputs may also be inferred.
5.7.2. Key storage attestation
Use case name: Key storage AttestationWho will use it: secure key storage subsystems
Message Flow: TBD
Attester: device platform
Relying Party: internet peers
Claims used as evidence: TBD
Description: This use case convinces the relying party only about the provenance of a private key by providing claims of the storage security of the private key. This can be conceived as a subset of the previous case, but may be apply very specifically to just a keystore. Additional details associated with the private key may be provided as well, including limitations on usage of the key.
Key storage attestations may be consumed by systems provisioning public key certificates for devices or human users. In these cases, attestations may be incorporated into certificate request protocols (e.g., EST {#rfc7030}, CMP {#rfc4210}, ACME {#rfc8555}, SCEP [I-D.gutmann-scep], etc.) and processed by registration authorities or certification authorities prior to determining contents for any issued certificate.
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Internet-Draft useful RATS November 2020 5.7.3. End user authorizationUse case name: End User authorization
Who will use it: authorization systems
Message Flow: TBD
Attester: device platform
Relying Party: internet peers
Claims used as evidence: TBD
Description: This use case convinces the relying party that the digital signatures made by the indicated key pair were done with the approval of the end-user/device-operator. This may also be considered possible subset of the device attestation above, but the attestation may be on a case-by-case basis. The nature of the approval by the end-user would be indicated. Examples include: the user unlocked the device, the user viewed some message and acknowledge it inside an app, the message was displayed to the user via out-of-app control mechanism. The acknowledgements could include selecting options on the screen, pushing physical buttons, scanning fingerprints, proximity to other devices (via bluetooth beacons, chargers, etc)
5.8. Geographic attestation
Use case name: Location attestationWho will use it: geo-fenced systems
Message Flow: passport (probably)
Attester: secure GPS system(s)
Relying Party: internet peers
Claims used as evidence: TBD
Description: The relying party wants to know the physical location (on the planet earth) of the device. This may be provided directly by a GPS/GLONASS/Galileo module that is incorporated into a TPM. This may also be provided by collecting other proximity messages from other device that the relying party can form a trust relationship with.
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Internet-Draft useful RATS November 2020 5.8.1. I am hereThe simplest use case is the claim of some specific coordinates.
5.8.2. I am near
The second use case is the claim that some other devices are nearby. This may be absolute ("I am near device X, which claims to be at location A"), or just relative, ("I am near device X"). This use could use "I am here" or "I am near" claims from a 1:1 basis with device X, or use some other protocol. The nature of how the proximity was established would be part of this claim. In order to defeat a variety of mechanisms that might attempt to proxy ("wormhole") radio communications, highly precise clocks may be required, and there may also have to be attestations as to the precision of those clocks.An additional example of being near would be for the case where two smartphones can establish that they are together by recording a common random movement, such as both devices being shaken together. Each device may validate the claim from the other (in a disconnected fashion), or a third party may validate the claim as the relying party.
This could be used to establish that a medical professional was in proximity of a patient with implanted devices who needs help.
5.8.3. You are here
A third way to establish location is for a third party to communicate directly with the relying party. The nature of how this trust is established (and whether it is done recursively) is outside of the scope here. What is critical is that the identity of "You" can be communicated through the third party in a way that the relying party can use, but other intermediaries can not view.
5.9. Connectivity attestation
Use case name: Connectivity attestationWho will use it: entertainment systems
Message Flow: TBD Attester: hardware-manufacturer/TEE
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Relying Party: connected peerClaims used as evidence: TBD
Description: The relying party wants to know what devices are connected. A typical situation would be a media owner needing to know what TV device is connected via HDMI and if High-bandwidth Digital Content Protection (HDCP) is intact.
5.10. Component connectivity attestation
Use case name: Component connectivityWho will use it: chassis systems with pluggable components
Message Flow: background check
Attester: line card
Relying Party: management/control plane software
Claims used as evidence: TBD
Description: A management controller or similar hardware component wants to know what peripherals, rack scale device or other dynamically configurable components are currently attached to the platform that is under management controller control. The management controller may serve as attestation verifier over a local bus or backplane but may also aggregate local attestation results and act as a platform attester to a remote verifier.
5.11. Device provenance attestation
Use case name: RIV - Device ProvenanceWho will use it: Industrial IoT devices
Message Flow: passport
Attester: network management station
Relying Party: a network entity
Claims used as evidence: TBD Description: A newly manufactured device needs to be onboarded into a network where many if not all device management duties are performed by the network owner. The device owner wants to verify the device originated from a legitimate vendor. A cryptographic device identity such as an IEEE802.1AR is embedded during manufacturing and a certificate identifying the device is delivered to the owner onboarding agent. The device authenticates using its 802.1AR IDevID to prove it originated from the expected vendor.
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The device chain of custody from the original device manufacturer to the new owner may also be verified as part of device provenance attestation. The chain of custody history may be collected by a cloud service or similar capability that the supply chain and owner agree to use.[I-D.fedorkow-rats-network-device-attestation] section 1.2 refers to this as "Provable Device Identity", and section 2.3 details the parties.
5.12. DNS privacy policy
Use case name: DNS-over-TLS or DNS-over-HTTPS server privacy policyWho will use it: enterprises and browsers and BYOD operating systems
Message Flow: passport
Attester: review agency
Relying Party: browsers and operating systems
Claims used as evidence: DNS server identity, privinfo (see draft-
reddy-dprive-dprive-privacy-policy )
Description: Users want to control how their DNS queries are handled
by DNS servers so they can configure their system to use DNS servers that comply with their privacy expectations.
This use case communicates an attestion from a DoH server to a web browser or equivalent in a desktop or mobile operating system. The attester is a third party which has performed some kind of review of the DNS server. This may include significant levels of Device Capability attestation as to what is running and how it is configured (see Section 5.1), in which case this is a form of Proxy Root of Trust (Section 5.1.3).
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Internet-Draft useful RATS November 2020 5.13. Safety Critical SystemsUse case name: Safety Critical Systems
Who will use it: Power plants and other systems that need to assert their current state, but which can not accept any inputs from the outside. The corollory system is a black-box (such as in an aircraft), which needs to log the state of a system, but which can never initiate a handshake.
Message Flow: background check
Attester: web services and other sources of status/sensor
information
Relying Party: open
Claims used as evidence: the beginning and ending time as endorsed by a Time Stamp Authority, represented by a time stamp token. The real time clock of the system itself. A Root of Trust for time; the TPM has a relative time from startup.
Description: These requirements motivate the creation of the Time
Base Unidirectional Attestation (TUDA) [I-D.birkholz-rats-tuda], the output of TUDA are typically a secure audit log, where freshness is determined by synchronization to an source of external time.
The freshness is preserved in the evidence by the use of a Time Stamp Authority (TSA) which provides Time Stamp Tokens (TST).
5.14. Trusted Path Routing
Use case name: Trusted Path RoutingWho will use it: Service Providers want to offer a trustworthy transport service to Government, Military, Financial, and Medical end-users.
Message Flow: background check model for a centralized controller
based alternative, and passport model for a router/switch distributed alternative.
Attester: Routers/switches
Relying Party: Network Controllers and Peer Routers/Switches Claims used as evidence: TPM Quotes, log entries passed into TPM PCRs, trustworthiness levels appraised by Verifiers, and included in passports.
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Description: There are end-users who believe encryption technologieslike IPsec alone are insufficient to protect the confidentiality of their highly sensitive traffic flows. These end-users want their sensitive flows to be forwarded across just those network devices currently appraised as trustworthy by the TCG-RIV use case.
[I-D.voit-rats-trusted-path-routing] discusses two alternatives for exchanging traffic with end-user customer identified "sensitive subnets". Traffic going to and from these subnets will transit a path where the IP layer and above are only interpretable by those network devices recently evaluated as trustworthy.
These two alternatives are:
Centralized Trusted Path Routing: For sensitive subnets, trusted end-to-end paths are pre-assigned through a network provider domain. Along these paths, attestation evidence of potentially transited components has been assessed. Each path is guaranteed to only include devices meeting the needs of a formally defined trustworthiness level.
Distributed Trusted Path Routing: Through the exchange of
attestation evidence between peering network devices, a trusted topology is established and maintained. Only devices meeting the needs of a formally defined trustworthiness level are included as members of this topology. Traffic exchanged with sensitive subnets is forwarded into this topology.
6. Technology users for RATS. 6.1. Trusted Computing Group Remove Integrity Verification (TCG-RIV)The TCG RIV Reference Document addresses the problem of knowing if a networking device should be part of a network, if it belongs to the operator, and if it is running appropriate software. The work covers most of the use cases in Section 5.1.
This proposal is available as [I-D.fedorkow-rats-network-device-attestation]. The goal is to be multi-vendor, scalable and extensible. The proposal intentionally limits itself to:
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o "non-privacy-preserving applications (i.e., networking, Industrial IoT )",o the firmware is provided by the device manufacturer
o there is a manufacturer installed hardware root of trust (such as a TPM and boot ROM)
Service providers and enterprises deploy hundreds of routers, many of them in remote locations where they're difficult to access or secure. The point of remote attestation is to:
o identify a remote box in a way that's hard to spoof
o report the inventory of software was launched on the box in a way that cannot be spoofed, that is undetectably altered by a "Lying Endpoint"
The use case described is to be able to monitor the authenticity of software versions and configurations running on each device. This allows owners and auditors to detect deviation from approved software and firmware versions and configurations, potentially identifying infected devices. [RFC5209]
Attestation may be performed by network management systems. Networking Equipment is often highly interconnected, so it's also possible that attestation could be performed by neighboring devices.
Specifically listed to be out of scope for the first generation includes: Linux processes, composite assemblies of hardware/software created by end-customers, and equipment that uses Sleep or Hibernate modes. There is an intention to cover some of these are topics in future versions of the documents.
The TCG-RIV Attestation leverages the TPM to make a series of measurements during the boot process, and to have the TPM sign those measurements. The resulting "PCR" hashes are then available to an external verifier.
A critical component of the RIV is compatibility with existing TPM practice for attestation proceedures, as spelled out in the TCG TAP Informational Model [tapinfomodel] and TPM architecture specifications [tpmarchspec].
The TCG uses the following terminology:
o Device Manufacturer o Attester ("device under attestation")
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o Verifier (Network Management Station)o "Explicit Attestation" is the TCG term for a static (platform) attestation
o "Implicit Attestation" is the TCG term for a session attestation
o Reference Integrity Measurements (RIM), which are signed my device manufacturer and integrated into firmware.
o Quotes: measured values (having been signed), and RIMs
o Reference Integrity Values (RIV)
o devices have a Initial Attestation Key (IAK), which is provisioned at the same time as the IDevID [ieee802-1AR]
o PCR - Platform Configuration Registry (deals with hash chains)
The TCG document builds upon a number of IETF technologies: SNMP (Attestation MIB), YANG, XML, JSON, CBOR, NETCONF, RESTCONF, CoAP, TLS and SSH. The TCG document leverages the 802.1AR IDevID and LDevID processes.
6.2. Android Keystore system
[keystore] describes a system used in smart phones that run the Android operation system. The system is primarily a software container to contain and control access to cryptographic keys, and therefore provides many of the same functions that a hardware Trusted Platform Module might provide.The uses described in section Section 5.7 are the primary focus.
On hardware which is supported, the Android Keystore will make use of whatever trusted hardware is available, including use of a Trusted Execution Environment (TEE) or Secure Element (SE). The Keystore therefore abstracts the hardware, and guarantees to applications that the same APIs can be used on both more and less capable devices.
A great deal of focus from the Android Keystore seems to be on providing fine-grained authorization of what keys can be used by which applications.
XXX - clearly there must be additional (intended?) use cases that provide some kind of attestation. Android 9 on Pixel 2 and 3 can provided protected confirmation messages. This uses hardware access from the TPM/TEE to display a message directly to the user, and receives confirmation directly from the user. A hash of the contents of the message can provided in an attestation that the device provides.
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In addition, the Android Keystore provides attestation information about itself for use by FIDO.QUOTE: Finally, the Verified Boot state is included in key attestation certificates (provided by Keymaster/Strongbox) in the deviceLocked and verifiedBootState fields, which can be verified by apps as well as passed onto backend services to remotely verify boot integrity
6.3. Fast IDentity Online (FIDO) Alliance
The FIDO Alliance [fido] has a number of specifications aimed primarily at eliminating the need for passwords for authentication to online services. The goal is to leverage asymmetric cryptographic operations in common browser and smart-phone platforms so that users can easily authentication.The use cases of Section 5.7 are primary.
FIDO specifications extend to various hardware second factor authentication devices.
Terminology includes:
o "relying party" validates a claim
o "relying party application" makes FIDO Authn calls
o "browser" provides the Web Authentication JS API
o "platform" is the base system
o "internal authenticator" is some credential built-in to the device
o "external authenticator" may be connected by USB, bluetooth, wifi, and may be an stand-alone device, USB connected key, phone or watch.
FIDO2 had a Key Attestation Format [fidoattestation], and a Signature Format [fidosignature], but these have been combined into the W3C document [fido_w3c] specification. A FIDO use case involves the relying party receiving a device attestation about the biometric system that performs the identication of the human. It is the state of the biometric system that is being attested to, not the identity of the human!
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FIDO does provides a transport in the form of the WebAuthn and FIDO CTAP protocols.According to [fidotechnote] FIDO uses attestation to make claims about the kind of device which is be used to enroll. Keypairs are generated on a per-device _model_ basis, with a certificate having a trust chain that leads back to a well-known root certificate. It is expected that as many as 100,000 devices in a production run would have the same public and private key pair. One assumes that this is stored in a tamper-proof TPM so it is relatively difficult to get this key out. The use of this key attests to the the device type, and the kind of protections for keys that the relying party may assume, not to the identity of the end user.
7. Examples of Existing Attestation Formats.
This section provides examples of some existing attestation formats.
7.1. Android Keystore
Android Keystore attestations take the form of X.509 certificates. The examples below package the attestation certificate along with intermediate CA certificates required to validate the attestation as a certificates-only SignedData message [RFC5652]. The trust anchor is available here: [keystore_attestation].The attestations below were generated using the generateKeyPair method from the DevicePolicyManager class using code similar to the following. KeyGenParameterSpec.Builder builder = null; if(hasStrongBox) {
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builder = new KeyGenParameterSpec.Builder(
m_alias,
KeyProperties.PURPOSE_SIGN | KeyProperties.PURPOSE_VERIFY | KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT)
.setKeySize(2048)
.setDigests(KeyProperties.DIGEST_NONE, KeyProperties.DIGEST_SHA256) .setBlockModes(KeyProperties.BLOCK_MODE_CBC, KeyProperties.BLOCK_MODE_GCM) .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_RSA_PKCS1, KeyProperties.ENCRYPTION_PADDING_RSA_OAEP) .setSignaturePaddings(KeyProperties.SIGNATURE_PADDING_RSA_PSS, KeyProperties.SIGNATURE_PADDING_RSA_PKCS1) .setUserAuthenticationRequired(false) .setIsStrongBoxBacked(true) .setUnlockedDeviceRequired(true); } else {builder = new KeyGenParameterSpec.Builder(
m_alias,
KeyProperties.PURPOSE_SIGN | KeyProperties.PURPOSE_VERIFY | KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT)
.setKeySize(2048)
.setDigests(KeyProperties.DIGEST_NONE, KeyProperties.DIGEST_SHA256, KeyProperties.DIGEST_SHA384, KeyProperties.DIGEST_SHA512) .setBlockModes(KeyProperties.BLOCK_MODE_CBC, KeyProperties.BLOCK_MODE_CTR,KeyProperties.BLOCK_MODE_GCM) .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_RSA_PKCS1, KeyProperties.ENCRYPTION_PADDING_RSA_OAEP) .setSignaturePaddings(KeyProperties.SIGNATURE_PADDING_RSA_PSS, KeyProperties.SIGNATURE_PADDING_RSA_PKCS1) .setUserAuthenticationRequired(false) .setIsStrongBoxBacked(false) .setUnlockedDeviceRequired(true); } builder.setAttestationChallenge(challenge_bytes);KeyGenParameterSpec keySpec = builder.build(); AttestedKeyPair akp = dpm.generateKeyPair(componentName, algorithm, keySpec, idAttestationFlags);
7.1.1. TEE
Annotations included below are delimited by ASN.1 comments, i.e., -. Annotations should be consistent with structures described here: [keystore_attestation].0 1172: SEQUENCE { 4 764: SEQUENCE { 8 3: [0] {
10 1: INTEGER 2
: }
13 1: INTEGER 1 16 13: SEQUENCE { 18 9: OBJECT IDENTIFIER
: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
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29 0: NULL: }
31 27: SEQUENCE { 33 25: SET { 35 23: SEQUENCE { 37 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) 42 16: PrintableString 'c6047571d8f0d17c' : } : } : } 60 32: SEQUENCE { 62 13: UTCTime 01/01/1970 00:00:00 GMT 77 15: GeneralizedTime 07/02/2106 06:28:15 GMT
: }
94 31: SEQUENCE { 96 29: SET { 98 27: SEQUENCE { 100 3: OBJECT IDENTIFIER commonName (2 5 4 3) 105 20: UTF8String 'Android Keystore Key' : } : } : } 127 290: SEQUENCE { 131 13: SEQUENCE { 133 9: OBJECT IDENTIFIER rsaEncryption (1 2 840 113549 1 1 1) 144 0: NULL
: }
146 271: BIT STRING, encapsulates { 151 266: SEQUENCE { 155 257: INTEGER : 00 B5 3A 83 61 A2 85 CC D2 D6 25 7F 07 0B B4 A0 : F6 FE 05 01 C9 55 CB 0D 18 D2 C6 79 BA 82 12 67 : 75 8D 5B F3 24 D3 F8 EA 99 82 7D 1F 5E CD 77 D6 : 99 11 13 FF 18 C9 3D 4D 01 C5 8E E9 04 E7 17 E2 : 88 12 2B B9 A1 77 2F C2 4F 57 78 98 4E E3 DE 7A : 1B 18 BE D3 ED C9 59 A0 24 50 E1 FA AC 81 B6 DA : 80 B0 BD 48 AD 26 9C 4A 4E CE 54 17 58 C1 F4 F8 : 7F 3C 5D 8F C8 2C 2A 7B 18 95 B3 D4 E0 3A C8 9D : [ Another 129 bytes skipped ]
416 3: INTEGER 65537
: } : } : } 421 347: [3] { 425 343: SEQUENCE { 429 14: SEQUENCE { 431 3: OBJECT IDENTIFIER keyUsage (2 5 29 15) 436 1: BOOLEAN TRUE 439 4: OCTET STRING, encapsulates { 441 2: BIT STRING 4 unused bits : '1100'B : } : } 445 323: SEQUENCE { 449 10: OBJECT IDENTIFIER '1 3 6 1 4 1 11129 2 1 17' 461 307: OCTET STRING, encapsulates { -- Attestation Extension 465 303: SEQUENCE { -- KeyDescription 469 1: INTEGER 2 -- attestationVersion (KM3) 472 1: ENUMERATED 1 -- attestationSecurityLevel (TrustedEnv.) 475 1: INTEGER 3 -- keymasterVersion 478 1: ENUMERATED 1 -- keymasterSecurityLevel (TrustedEnv.) 481 9: OCTET STRING 'challenge' -- attestationChallenge 492 0: OCTET STRING -- reserved
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: Error: Object has zero length.494 44: SEQUENCE { -- softwareEnforced 496 8: [701] { -- creationDateTime 500 6: INTEGER 01 64 47 2A 4B 64
: }
508 28: [709] { -- attestationApplicationId 512 26: OCTET STRING, encapsulates { 514 24: SEQUENCE { -- AttestationApplicationId 516 20: SET { -- package_infos 518 18: SEQUENCE { -- AttestationPackageInfo 520 13: OCTET STRING 'AndroidSystem' -- package_name 535 1: INTEGER 1 -- version : } : }
538 0: SET {} -- signature_digests
: } : } : } : } 540 229: SEQUENCE { -- hardwareEnforced 543 14: [1] { -- purpose 545 12: SET { 547 1: INTEGER 0 -- KeyPurpose.ENCRYPT 550 1: INTEGER 1 -- KeyPurpose.DECRYPT 553 1: INTEGER 2 -- KeyPurpose.SIGN 556 1: INTEGER 3 -- KeyPurpose.VERIFY : } : } 559 3: [2] { -- algorithm 561 1: INTEGER 1 -- Algorithm.RSA
: }
564 4: [3] { -- keySize 566 2: INTEGER 2048
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: }570 11: [5] { -- digest 572 9: SET { 574 1: INTEGER 4 -- Digest.SHA256 577 1: INTEGER 5 -- Digest.SHA384 580 1: INTEGER 6 -- Digest.SHA512 : } : } 583 14: [6] { -- padding 585 12: SET { 587 1: INTEGER 4 -- PaddingMode.RSA_PKCS1_1_5_ENCRYPT 590 1: INTEGER 2 -- PaddingMode.RSA_OAEP 593 1: INTEGER 3 -- PaddingMode.RSA_PKCS1_1_5_SIGN 596 1: INTEGER 5 -- PaddingMode.RSA_PSS : } : } 599 5: [200] { -- rsaPublicExponent 603 3: INTEGER 65537
: }
608 2: [503] { -- noAuthRequired 612 0: NULL -- documentation indicates this is a Boolean
: }
614 3: [702] { -- origin 618 1: INTEGER 0 -- KeyOrigin.GENERATED
: }
621 2: [703] { -- rollbackResistant 625 0: NULL -- documentation indicates this is a Boolean
: }
627 42: [704] { -- rootOfTrust 631 40: SEQUENCE { -- verifiedBootKey 633 32: OCTET STRING : 19 62 B0 53 85 79 FF CE 9A C9 F5 07 C4 6A FE 3B : 92 05 5B AC 71 46 46 22 83 C8 5C 50 0B E7 8D 82 667 1: BOOLEAN TRUE -- deviceLocked 670 1: ENUMERATED 0 -- verifiedBootState (verified) : } : } 673 5: [705] { -- osVersion 677 3: INTEGER 90000 -- Android P
: }
682 5: [706] { -- osPatchLevel 686 3: INTEGER 201806 -- June 2018
: }
691 8: [710] { -- attestationIdBrand 695 6: OCTET STRING 'google'
: }
703 9: [711] { -- attestationIdDevice 707 7: OCTET STRING 'walleye'
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: }716 9: [712] { -- attestationIdProduct 720 7: OCTET STRING 'walleye'
: }
729 14: [713] { -- attestationIdSerial 733 12: OCTET STRING 'HT83K1A03849'
: }
747 8: [716] { -- attestationIdManufacturer 751 6: OCTET STRING 'Google'
: }
759 9: [717] { -- attestationIdModel 763 7: OCTET STRING 'Pixel 2' : } : } : } : } : } : } : } : } 772 13: SEQUENCE { 774 9: OBJECT IDENTIFIER sha256WithRSAEncryption (1 2 840 113549 1 1 11) 785 0: NULL
: }
787 385: BIT STRING
: 05 41 B9 13 11 53 93 A2 02 62 1F 15 35 8E D9 7C : A1 D5 2E ED 13 AC 24 26 B2 A1 2F EE B4 0C 4D 71 : DC 9F 55 EC A1 F6 64 62 F2 73 A8 7E FC 48 63 29 : 1E F5 0D 48 F3 73 43 0C 00 E0 D4 07 86 A6 A4 38 : 0E A8 47 0F 27 01 01 31 52 F6 62 8A 4B 80 BE 72 : FB 02 E7 56 84 CA CA 4D C3 6C 7C B2 BA C7 D7 9B : C5 9D 90 65 4E F5 54 8F 25 CC 11 7F 8E 77 10 6A : 6E 9F 80 89 48 8B 1D 51 AA 3B B7 C5 24 3C 28 B1 : [ Another 256 bytes skipped ] : } 0 1304: SEQUENCE { 4 768: SEQUENCE { 8 3: [0] {
10 1: INTEGER 2
: }
13 10: INTEGER 10 34 53 32 94 08 68 79 38 72 25 13: SEQUENCE { 27 9: OBJECT IDENTIFIER
: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
38 0: NULL
: }
40 27: SEQUENCE { 42 25: SET { 44 23: SEQUENCE { 46 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) 51 16: PrintableString '87f4514475ba0a2b' : } : } : } 69 30: SEQUENCE { 71 13: UTCTime 26/05/2016 17:14:51 GMT 86 13: UTCTime 24/05/2026 17:14:51 GMT
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: }101 27: SEQUENCE { 103 25: SET { 105 23: SEQUENCE { 107 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) 112 16: PrintableString 'c6047571d8f0d17c' : } : } : } 130 418: SEQUENCE { 134 13: SEQUENCE { 136 9: OBJECT IDENTIFIER rsaEncryption (1 2 840 113549 1 1 1) 147 0: NULL
: }
149 399: BIT STRING, encapsulates { 154 394: SEQUENCE { 158 385: INTEGER : 00 B3 01 0D 78 BC 06 33 25 CA D6 A7 2C EF 49 05 : 4C C1 77 36 F2 E5 7B E8 4C 0A 87 8F 77 6A 09 45 : 9B AC E8 72 DA E2 0E 20 3D 68 30 A5 86 26 14 77 : AD 7E 93 F5 1D 38 A9 DB 5B FE B2 B8 1A 7B CD 22 : 3B 17 98 FC 1F 4F 77 2D 92 E9 DE 5F 6B 02 09 4E : 99 86 53 98 1C 5E 23 B6 A4 61 53 A5 FB D1 37 09 : DB C0 0A 40 E9 28 E6 BE E2 8E 57 94 A9 F2 13 3A : 11 40 D2 34 99 A6 B4 F3 99 F2 5D 4A 5D 6A 6C 4B : [ Another 257 bytes skipped ]
547 3: INTEGER 65537
: } : } : } 552 221: [3] { 555 218: SEQUENCE { 558 29: SEQUENCE { 560 3: OBJECT IDENTIFIER subjectKeyIdentifier (2 5 29 14) 565 22: OCTET STRING, encapsulates { 567 20: OCTET STRING : 7B 7B F8 43 CA 1F 0F 96 27 0F 10 6F 7D 0C 23 14 : 72 8F 1D 80 : } : } 589 31: SEQUENCE { 591 3: OBJECT IDENTIFIER authorityKeyIdentifier (2 5 29 35) 596 24: OCTET STRING, encapsulates { 598 22: SEQUENCE { 600 20: [0] : 0E 55 6F 46 F5 3B 77 67 E1 B9 73 DC 55 E6 AE EA : B4 FD 27 DD : } : } : } 622 12: SEQUENCE { 624 3: OBJECT IDENTIFIER basicConstraints (2 5 29 19) 629 1: BOOLEAN TRUE 632 2: OCTET STRING, encapsulates { 634 0: SEQUENCE {} : } : } 636 14: SEQUENCE { 638 3: OBJECT IDENTIFIER keyUsage (2 5 29 15) 643 1: BOOLEAN TRUE 646 4: OCTET STRING, encapsulates { 648 2: BIT STRING 7 unused bits : '1'B (bit 0) : } : } 652 36: SEQUENCE { 654 3: OBJECT IDENTIFIER nameConstraints (2 5 29 30) 659 29: OCTET STRING, encapsulates { 661 27: SEQUENCE { 663 25: [0] { 665 23: SEQUENCE { 667 21: [2] 'invalid;email:invalid' : } : } : } : } : } 690 84: SEQUENCE { 692 3: OBJECT IDENTIFIER cRLDistributionPoints (2 5 29 31) 697 77: OCTET STRING, encapsulates { 699 75: SEQUENCE { 701 73: SEQUENCE { 703 71: [0] { 705 69: [0] { 707 67: [6] : 'https://android.googleapis.com/attestation/crl/1' : '0345332940868793872' : } : } : } : } : } : } : } : } : } 776 13: SEQUENCE { 778 9: OBJECT IDENTIFIER sha256WithRSAEncryption (1 2 840 113549 1 1 11) 789 0: NULL
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: }791 513: BIT STRING
: 69 13 A7 56 B3 9F E1 2B CE A2 09 89 E5 DC 03 B4 : B6 FF F6 1E 96 C7 62 C2 31 D1 B3 D6 1A 9E 36 CF : C2 FC 0E 06 FA 0E CF B5 2D F8 19 D6 13 96 0B 56 : B0 EE 86 3B B1 B8 38 70 4E 57 EB D9 60 DC 58 74 : FE C8 EB A5 78 9F B7 19 5C F0 80 CF 29 16 6B 04 : 3A 5D 7C 2E 5F 11 12 36 BE 46 29 45 04 41 8F B5 : AB C6 31 5F 23 28 0C F2 7C 48 4A F6 43 AA 50 D0 : 53 96 1E AD 7C A3 89 96 BB 8B BF 2D 9A 0C 16 35 : [ Another 384 bytes skipped ] : } 0 1393: SEQUENCE { 4 857: SEQUENCE { 8 3: [0] {
10 1: INTEGER 2
: }
13 10: INTEGER 03 88 26 67 60 65 89 96 85 74 25 13: SEQUENCE { 27 9: OBJECT IDENTIFIER
: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
38 0: NULL
: }
40 27: SEQUENCE { 42 25: SET { 44 23: SEQUENCE { 46 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) 51 16: PrintableString 'f92009e853b6b045' : } : } : } 69 30: SEQUENCE { 71 13: UTCTime 26/05/2016 17:01:32 GMT 86 13: UTCTime 24/05/2026 17:01:32 GMT
: }
101 27: SEQUENCE { 103 25: SET { 105 23: SEQUENCE { 107 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) 112 16: PrintableString '87f4514475ba0a2b' : } : } : } 130 546: SEQUENCE { 134 13: SEQUENCE { 136 9: OBJECT IDENTIFIER rsaEncryption (1 2 840 113549 1 1 1) 147 0: NULL
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: }149 527: BIT STRING, encapsulates { 154 522: SEQUENCE { 158 513: INTEGER : 00 D2 60 D6 45 85 E3 E2 23 79 5A DA 45 57 A7 D8 : 5B AF BD 9A 37 CB FA 97 C0 65 44 9D 3A C6 47 F6 : 0D 0B A2 74 12 CA F7 4B B9 5F FB B4 EC 5A 2B D0 : 16 01 DE BE E2 FE D2 76 0D 75 C4 B1 6A CB 3A 67 : 07 21 E0 D5 19 68 C8 1B 01 A2 24 02 FE AD 40 D6 : A7 98 16 0F A2 98 2E A7 AD 75 34 84 6F F8 CF 8A : A1 0E 90 33 40 9E D0 86 26 57 71 CE FF CF 52 E1 : F0 F9 2B 7E 68 62 03 D8 FD FD 02 53 03 19 AC 28 : [ Another 385 bytes skipped ]
675 3: INTEGER 65537
: } : } : } 680 182: [3] { 683 179: SEQUENCE { 686 29: SEQUENCE { 688 3: OBJECT IDENTIFIER subjectKeyIdentifier (2 5 29 14) 693 22: OCTET STRING, encapsulates { 695 20: OCTET STRING : 0E 55 6F 46 F5 3B 77 67 E1 B9 73 DC 55 E6 AE EA : B4 FD 27 DD : } : } 717 31: SEQUENCE { 719 3: OBJECT IDENTIFIER authorityKeyIdentifier (2 5 29 35) 724 24: OCTET STRING, encapsulates { 726 22: SEQUENCE { 728 20: [0] : 36 61 E1 00 7C 88 05 09 51 8B 44 6C 47 FF 1A 4C : C9 EA 4F 12 : } : } : } 750 15: SEQUENCE { 752 3: OBJECT IDENTIFIER basicConstraints (2 5 29 19) 757 1: BOOLEAN TRUE 760 5: OCTET STRING, encapsulates { 762 3: SEQUENCE { 764 1: BOOLEAN TRUE : } : } : } 767 14: SEQUENCE { 769 3: OBJECT IDENTIFIER keyUsage (2 5 29 15) 774 1: BOOLEAN TRUE 777 4: OCTET STRING, encapsulates { 779 2: BIT STRING 1 unused bit : '1100001'B : } : } 783 80: SEQUENCE { 785 3: OBJECT IDENTIFIER cRLDistributionPoints (2 5 29 31) 790 73: OCTET STRING, encapsulates { 792 71: SEQUENCE { 794 69: SEQUENCE { 796 67: [0] { 798 65: [0] { 800 63: [6] : 'https://android.googleapis.com/attestation/crl/E' : '8FA196314D2FA18' : } : } : } : } : } : } : } : } : } 865 13: SEQUENCE { 867 9: OBJECT IDENTIFIER sha256WithRSAEncryption (1 2 840 113549 1 1 11) 878 0: NULL
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: }880 513: BIT STRING
: 0E 0D 71 4A 88 0A 58 53 B6 31 14 7D DA 22 31 C6 : 06 D6 EF 3B 22 4D D7 A5 C0 3F BF C6 B4 64 A3 FB : 92 C2 CC 67 F4 6C 24 25 49 6E F6 CB 08 D6 A8 0D : 94 06 7F 8C 8C 3C B1 77 CD C2 3F C7 5E A3 85 6D : F7 A5 94 13 CD 5A 5C F3 9B 0A 0D E1 82 42 F4 C9 : 3F AD FC FB 7C AA 27 04 CC 1C 12 45 15 EB E6 70 : A0 6C DE 77 77 54 9B 1F 02 05 76 03 A4 FC 6C 07 : F4 CB BB 59 F5 CB ED 58 D8 30 9B 6E 3C F7 76 C1 : [ Another 384 bytes skipped ] : } 0 1376: SEQUENCE { 4 840: SEQUENCE { 8 3: [0] {
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10 1: INTEGER 2: }
13 9: INTEGER 00 E8 FA 19 63 14 D2 FA 18 24 13: SEQUENCE { 26 9: OBJECT IDENTIFIER
: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
37 0: NULL
: }
39 27: SEQUENCE { 41 25: SET { 43 23: SEQUENCE { 45 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) 50 16: PrintableString 'f92009e853b6b045' : } : } : } 68 30: SEQUENCE { 70 13: UTCTime 26/05/2016 16:28:52 GMT 85 13: UTCTime 24/05/2026 16:28:52 GMT
: }
100 27: SEQUENCE { 102 25: SET { 104 23: SEQUENCE { 106 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) 111 16: PrintableString 'f92009e853b6b045' : } : } : } 129 546: SEQUENCE { 133 13: SEQUENCE { 135 9: OBJECT IDENTIFIER rsaEncryption (1 2 840 113549 1 1 1) 146 0: NULL
: }
148 527: BIT STRING, encapsulates { 153 522: SEQUENCE { 157 513: INTEGER : 00 AF B6 C7 82 2B B1 A7 01 EC 2B B4 2E 8B CC 54 : 16 63 AB EF 98 2F 32 C7 7F 75 31 03 0C 97 52 4B : 1B 5F E8 09 FB C7 2A A9 45 1F 74 3C BD 9A 6F 13 : 35 74 4A A5 5E 77 F6 B6 AC 35 35 EE 17 C2 5E 63 : 95 17 DD 9C 92 E6 37 4A 53 CB FE 25 8F 8F FB B6 : FD 12 93 78 A2 2A 4C A9 9C 45 2D 47 A5 9F 32 01 : F4 41 97 CA 1C CD 7E 76 2F B2 F5 31 51 B6 FE B2 : FF FD 2B 6F E4 FE 5B C6 BD 9E C3 4B FE 08 23 9D : [ Another 385 bytes skipped ]
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674 3: INTEGER 65537: } : } : } 679 166: [3] { 682 163: SEQUENCE { 685 29: SEQUENCE { 687 3: OBJECT IDENTIFIER subjectKeyIdentifier (2 5 29 14) 692 22: OCTET STRING, encapsulates { 694 20: OCTET STRING : 36 61 E1 00 7C 88 05 09 51 8B 44 6C 47 FF 1A 4C : C9 EA 4F 12 : } : } 716 31: SEQUENCE { 718 3: OBJECT IDENTIFIER authorityKeyIdentifier (2 5 29 35) 723 24: OCTET STRING, encapsulates { 725 22: SEQUENCE { 727 20: [0] : 36 61 E1 00 7C 88 05 09 51 8B 44 6C 47 FF 1A 4C : C9 EA 4F 12 : } : } : } 749 15: SEQUENCE { 751 3: OBJECT IDENTIFIER basicConstraints (2 5 29 19) 756 1: BOOLEAN TRUE 759 5: OCTET STRING, encapsulates { 761 3: SEQUENCE { 763 1: BOOLEAN TRUE : } : } : } 766 14: SEQUENCE { 768 3: OBJECT IDENTIFIER keyUsage (2 5 29 15) 773 1: BOOLEAN TRUE 776 4: OCTET STRING, encapsulates { 778 2: BIT STRING 1 unused bit : '1100001'B : } : } 782 64: SEQUENCE { 784 3: OBJECT IDENTIFIER cRLDistributionPoints (2 5 29 31) 789 57: OCTET STRING, encapsulates { 791 55: SEQUENCE { 793 53: SEQUENCE { 795 51: [0] { 797 49: [0] { 799 47: [6] : 'https://android.googleapis.com/attestation/crl/' : } : } : } : } : } : } : } : } : } 848 13: SEQUENCE { 850 9: OBJECT IDENTIFIER sha256WithRSAEncryption (1 2 840 113549 1 1 11) 861 0: NULL
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: }863 513: BIT STRING
: 20 C8 C3 8D 4B DC A9 57 1B 46 8C 89 2F FF 72 AA : C6 F8 44 A1 1D 41 A8 F0 73 6C C3 7D 16 D6 42 6D : 8E 7E 94 07 04 4C EA 39 E6 8B 07 C1 3D BF 15 03 : DD 5C 85 BD AF B2 C0 2D 5F 6C DB 4E FA 81 27 DF : 8B 04 F1 82 77 0F C4 E7 74 5B 7F CE AA 87 12 9A : 88 01 CE 8E 9B C0 CB 96 37 9B 4D 26 A8 2D 30 FD : 9C 2F 8E ED 6D C1 BE 2F 84 B6 89 E4 D9 14 25 8B : 14 4B BA E6 24 A1 C7 06 71 13 2E 2F 06 16 A8 84 : [ Another 384 bytes skipped ] : }
7.1.2. Secure Element
The structures below are not annotated except where the difference is specific to the difference between the TEE structure shown above and artifacts emitted by StrongBox.0 5143: SEQUENCE { 4 9: OBJECT IDENTIFIER signedData (1 2 840 113549 1 7 2) 15 5128: [0] { 19 5124: SEQUENCE { 23 1: INTEGER 1 26 0: SET {} 28 11: SEQUENCE { 30 9: OBJECT IDENTIFIER data (1 2 840 113549 1 7 1)
: }
41 5100: [0] { 45 1114: SEQUENCE { 49 834: SEQUENCE { 53 3: [0] { 55 1: INTEGER 2
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: }58 1: INTEGER 1 61 13: SEQUENCE { 63 9: OBJECT IDENTIFIER
: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
74 0: NULL
: }
76 47: SEQUENCE { 78 25: SET { 80 23: SEQUENCE { 82 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) 87 16: PrintableString '90e8da3cadfc7820' : } : } 105 18: SET { 107 16: SEQUENCE { 109 3: OBJECT IDENTIFIER title (2 5 4 12) 114 9: UTF8String 'StrongBox' : } : } : } 125 30: SEQUENCE { 127 13: UTCTime 01/01/1970 00:00:00 GMT 142 13: UTCTime 23/05/2028 23:59:59 GMT
: }
157 31: SEQUENCE { 159 29: SET { 161 27: SEQUENCE { 163 3: OBJECT IDENTIFIER commonName (2 5 4 3) 168 20: UTF8String 'Android Keystore Key' : } : } : } 190 290: SEQUENCE { 194 13: SEQUENCE { 196 9: OBJECT IDENTIFIER
: rsaEncryption (1 2 840 113549 1 1 1)
207 0: NULL
: }
209 271: BIT STRING, encapsulates { 214 266: SEQUENCE { 218 257: INTEGER : 00 DE 98 94 D5 E5 05 98 E8 FC 73 4D 26 FB 48 6A : CA 06 A0 24 FA 05 D1 D2 32 10 46 F8 50 DD 3E 0D : DF 4F 95 53 D2 CB 10 1F 00 B2 62 15 1E 21 7E 05 : C6 10 AC EE 7A D8 69 F1 1F 32 C3 17 CA D7 07 BE : 3B 2B 83 0F B4 9C 3D C7 13 0B 9C 59 2F 1A 38 CE : A5 1D 95 A7 3C EE 70 6A CF 41 FF 55 3F E0 9C 69 : E5 A0 C1 19 EF 40 E9 40 FC 74 D3 3B 96 D9 0E C1 : C3 9D 14 10 0C A6 95 19 49 88 F4 AB 74 FC 86 A6 : [ Another 129 bytes skipped ]
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479 3: INTEGER 65537: } : } : } 484 399: [3] { 488 395: SEQUENCE { 492 14: SEQUENCE { 494 3: OBJECT IDENTIFIER keyUsage (2 5 29 15) 499 1: BOOLEAN TRUE 502 4: OCTET STRING, encapsulates { 504 2: BIT STRING 7 unused bits : '1'B (bit 0) : } : } 508 375: SEQUENCE { 512 10: OBJECT IDENTIFIER '1 3 6 1 4 1 11129 2 1 17' 524 359: OCTET STRING, encapsulates { 528 355: SEQUENCE { 532 1: INTEGER 3 535 1: ENUMERATED 2 -- attestationSecurityLevel (StrongBox) 538 1: INTEGER 4 541 1: ENUMERATED 2 -- attestationSecurityLevel (StrongBox) 544 9: OCTET STRING 'challenge' 555 0: OCTET STRING
: Error: Object has zero length.
557 53: SEQUENCE { 559 2: [509] { 563 0: NULL
: }
565 11: [701] { 569 9: INTEGER 00 FF FF FF FF FF E5 99 78
: }
580 28: [709] { 584 26: OCTET STRING, encapsulates { 586 24: SEQUENCE { 588 20: SET { 590 18: SEQUENCE { 592 13: OCTET STRING 'AndroidSystem' 607 1: INTEGER 1 : } : }
610 0: SET {}
: } : } : } : } 612 271: SEQUENCE { 616 14: [1] { 618 12: SET { 620 1: INTEGER 0 623 1: INTEGER 1 626 1: INTEGER 2 629 1: INTEGER 3 : } : } 632 3: [2] { 634 1: INTEGER 1
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: }637 4: [3] { 639 2: INTEGER 2048
: }
643 8: [4] { 645 6: SET { 647 1: INTEGER 2 650 1: INTEGER 32 : } : } 653 8: [5] { 655 6: SET { 657 1: INTEGER 0 660 1: INTEGER 4 : } : } 663 14: [6] { 665 12: SET { 667 1: INTEGER 2 670 1: INTEGER 3 673 1: INTEGER 4 676 1: INTEGER 5 : } : } 679 2: [503] { 683 0: NULL
: }
685 3: [702] { 689 1: INTEGER 0
: }
692 76: [704] { 696 74: SEQUENCE { 698 32: OCTET STRING : 61 FD A1 2B 32 ED 84 21 4A 9C F1 3D 1A FF B7 AA : 80 BD 8A 26 8A 86 1E D4 BB 7A 15 17 0F 1A B0 0C 732 1: BOOLEAN TRUE 735 1: ENUMERATED 0 738 32: OCTET STRING : 77 96 C5 3D 0E 09 46 2B BA BB FB 7B 8A 65 F6 8D : EF 5C 46 88 BF 99 C4 1E 88 42 01 4D 1F 01 2D C5 : } : } 772 3: [705] { 776 1: INTEGER 0
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: }779 5: [706] { 783 3: INTEGER 201903
: }
788 8: [710] { 792 6: OCTET STRING 'google'
: }
800 10: [711] { 804 8: OCTET STRING 'blueline'
: }
814 10: [712] { 818 8: OCTET STRING 'blueline'
: }
828 11: [713] { 832 9: OCTET STRING '8A2X0KLUU'
: }
843 8: [716] { 847 6: OCTET STRING 'Google'
: }
855 9: [717] { 859 7: OCTET STRING 'Pixel 3'
: }
868 6: [718] { 872 4: INTEGER 20180905
: }
878 5: [719] { 882 3: INTEGER 201903 : } : } : } : } : } : } : } : } 887 13: SEQUENCE { 889 9: OBJECT IDENTIFIER
: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
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900 0: NULL: }
902 257: BIT STRING
: 83 EA 59 8D BE 37 4A D5 C0 FC F8 FB AC 8B 72 1E : A5 C2 3B 0C C0 04 1B C0 5A 18 A5 DF D4 67 1D B9 : 08 42 4B E2 2C AC 07 0F D8 0E 24 97 56 9E 14 F2 : D0 AC DD 1E FC DD 68 20 11 DF 88 B8 B6 22 AD 2B : DB 9C 2E 5C 3F AF 0B 8F 02 68 AA 34 4B 5E C8 75 : B1 1A 09 D2 19 41 24 61 65 97 2C 0D A4 78 43 A7 : 9A 27 B2 4E 24 11 4F FF E2 D8 04 56 39 75 B2 34 : D8 18 C7 25 F3 3F C0 6A 37 AB 49 B6 96 51 61 72 : [ Another 128 bytes skipped ] : }
1163 1181: SEQUENCE { 1167 645: SEQUENCE { 1171 3: [0] { 1173 1: INTEGER 2: }
1176 10: INTEGER 17 10 24 68 40 71 02 97 78 50 1188 13: SEQUENCE { 1190 9: OBJECT IDENTIFIER: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
1201 0: NULL
: }1203 47: SEQUENCE { 1205 25: SET { 1207 23: SEQUENCE { 1209 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) 1214 16: PrintableString 'ccd18b9b608d658e': } : }
1232 18: SET { 1234 16: SEQUENCE { 1236 3: OBJECT IDENTIFIER title (2 5 4 12) 1241 9: UTF8String 'StrongBox': } : } : }
1252 30: SEQUENCE { 1254 13: UTCTime 25/05/2018 23:28:47 GMT 1269 13: UTCTime 22/05/2028 23:28:47 GMT: }
1284 47: SEQUENCE { 1286 25: SET { 1288 23: SEQUENCE { 1290 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) 1295 16: PrintableString '90e8da3cadfc7820': } : }
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Internet-Draft useful RATS November 2020 1313 18: SET { 1315 16: SEQUENCE { 1317 3: OBJECT IDENTIFIER title (2 5 4 12) 1322 9: UTF8String 'StrongBox': } : } : }
1333 290: SEQUENCE { 1337 13: SEQUENCE { 1339 9: OBJECT IDENTIFIER: rsaEncryption (1 2 840 113549 1 1 1)
1350 0: NULL
: }1352 271: BIT STRING, encapsulates { 1357 266: SEQUENCE { 1361 257: INTEGER: 00 A5 09 D4 09 D2 30 19 36 34 71 FD 7D 41 89 E6 : 2C A5 9D 10 1B 4F 40 6A B0 5F 56 34 16 E6 EB D7 : F3 E9 C5 DC 20 F3 86 D1 77 19 D7 15 1F E7 EC 62 : DC 0A BC 64 E9 18 52 B0 AA B8 FF 58 6A E0 0F B8 : 56 AF 77 D3 CE 3C DC 48 52 DD B2 86 0D 76 17 7C : FD EE B4 E6 6E 0A 08 9E 06 CA 0F EC 4B B0 7C AF : EA 82 27 A8 C9 A7 63 DA 89 F6 30 BA 3C 3A E5 C6 : EF 11 06 42 8A 2E FE 19 BE F2 C7 3B 34 16 B2 E2 : [ Another 129 bytes skipped ]
1622 3: INTEGER 65537
: } : } : }1627 186: [3] { 1630 183: SEQUENCE { 1633 29: SEQUENCE { 1635 3: OBJECT IDENTIFIER subjectKeyIdentifier (2 5 29 14) 1640 22: OCTET STRING, encapsulates { 1642 20: OCTET STRING: 77 A4 AD DF 1D 29 89 CA 92 E3 BA DE 27 3C 70 DF : 36 03 7C 0C : } : }
1664 31: SEQUENCE { 1666 3: OBJECT IDENTIFIER: authorityKeyIdentifier (2 5 29 35)
1671 24: OCTET STRING, encapsulates { 1673 22: SEQUENCE { 1675 20: [0]: 1B 17 70 C6 97 DC 84 54 75 7C 3C 98 5C E6 1D 1D : 08 59 5D 53 : } : } : }
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Internet-Draft useful RATS November 2020 1697 15: SEQUENCE { 1699 3: OBJECT IDENTIFIER basicConstraints (2 5 29 19) 1704 1: BOOLEAN TRUE 1707 5: OCTET STRING, encapsulates { 1709 3: SEQUENCE { 1711 1: BOOLEAN TRUE: } : } : }
1714 14: SEQUENCE { 1716 3: OBJECT IDENTIFIER keyUsage (2 5 29 15) 1721 1: BOOLEAN TRUE 1724 4: OCTET STRING, encapsulates { 1726 2: BIT STRING 2 unused bits: '100000'B (bit 5) : } : }
1730 84: SEQUENCE { 1732 3: OBJECT IDENTIFIER cRLDistributionPoints (2 5 29 31) 1737 77: OCTET STRING, encapsulates { 1739 75: SEQUENCE { 1741 73: SEQUENCE { 1743 71: [0] { 1745 69: [0] { 1747 67: [6]: 'https://android.googleapis.com/attestation/crl/1' : '7102468407102977850' : } : } : } : } : } : } : } : } : }
1816 13: SEQUENCE { 1818 9: OBJECT IDENTIFIER: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
1829 0: NULL
: }
1831 513: BIT STRING
: 13 22 DA F2 92 93 CE C0 9F 70 40 C9 DA 85 6B 61 : 6F 8F BE E0 A4 04 55 C1 63 84 61 37 F5 4B 71 6D : 62 AA 6F BF 6C E8 48 03 AD 28 85 21 9E 3C 1C 91 : 48 EE 65 28 65 70 D0 BD 5B CC DB CE B1 F5 B5 C3 : CA 7A A9 C8 8A 68 12 8A CA 6A 85 A6 BC DA 36 E9 : B9 94 35 82 5B CA BC B6 9F 83 03 7F 21 6C EE 82 : C1 3F BD C1 41 4B DD 1A 6F 6C AF 4A 52 FC 19 19 : 17 AC 29 0C 5E D7 57 90 D5 B1 2B 36 29 1F 45 33 : [ Another 384 bytes skipped ] : }
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Internet-Draft useful RATS November 2020 2348 1376: SEQUENCE { 2352 840: SEQUENCE { 2356 3: [0] { 2358 1: INTEGER 2: }
2361 9: INTEGER 00 E8 FA 19 63 14 D2 FA 18 2372 13: SEQUENCE { 2374 9: OBJECT IDENTIFIER: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
2385 0: NULL
: }2387 27: SEQUENCE { 2389 25: SET { 2391 23: SEQUENCE { 2393 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) 2398 16: PrintableString 'f92009e853b6b045': } : } : }
2416 30: SEQUENCE { 2418 13: UTCTime 26/05/2016 16:28:52 GMT 2433 13: UTCTime 24/05/2026 16:28:52 GMT: }
2448 27: SEQUENCE { 2450 25: SET { 2452 23: SEQUENCE { 2454 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) 2459 16: PrintableString 'f92009e853b6b045': } : } : }
2477 546: SEQUENCE { 2481 13: SEQUENCE { 2483 9: OBJECT IDENTIFIER: rsaEncryption (1 2 840 113549 1 1 1)
2494 0: NULL
: }2496 527: BIT STRING, encapsulates { 2501 522: SEQUENCE { 2505 513: INTEGER: 00 AF B6 C7 82 2B B1 A7 01 EC 2B B4 2E 8B CC 54 : 16 63 AB EF 98 2F 32 C7 7F 75 31 03 0C 97 52 4B : 1B 5F E8 09 FB C7 2A A9 45 1F 74 3C BD 9A 6F 13 : 35 74 4A A5 5E 77 F6 B6 AC 35 35 EE 17 C2 5E 63 : 95 17 DD 9C 92 E6 37 4A 53 CB FE 25 8F 8F FB B6 : FD 12 93 78 A2 2A 4C A9 9C 45 2D 47 A5 9F 32 01 : F4 41 97 CA 1C CD 7E 76 2F B2 F5 31 51 B6 FE B2 : FF FD 2B 6F E4 FE 5B C6 BD 9E C3 4B FE 08 23 9D : [ Another 385 bytes skipped ]
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Internet-Draft useful RATS November 2020 3022 3: INTEGER 65537: } : } : }
3027 166: [3] { 3030 163: SEQUENCE { 3033 29: SEQUENCE { 3035 3: OBJECT IDENTIFIER subjectKeyIdentifier (2 5 29 14) 3040 22: OCTET STRING, encapsulates { 3042 20: OCTET STRING: 36 61 E1 00 7C 88 05 09 51 8B 44 6C 47 FF 1A 4C : C9 EA 4F 12 : } : }
3064 31: SEQUENCE { 3066 3: OBJECT IDENTIFIER: authorityKeyIdentifier (2 5 29 35)
3071 24: OCTET STRING, encapsulates { 3073 22: SEQUENCE { 3075 20: [0]: 36 61 E1 00 7C 88 05 09 51 8B 44 6C 47 FF 1A 4C : C9 EA 4F 12 : } : } : }
3097 15: SEQUENCE { 3099 3: OBJECT IDENTIFIER basicConstraints (2 5 29 19) 3104 1: BOOLEAN TRUE 3107 5: OCTET STRING, encapsulates { 3109 3: SEQUENCE { 3111 1: BOOLEAN TRUE: } : } : }
3114 14: SEQUENCE { 3116 3: OBJECT IDENTIFIER keyUsage (2 5 29 15) 3121 1: BOOLEAN TRUE 3124 4: OCTET STRING, encapsulates { 3126 2: BIT STRING 1 unused bit: '1100001'B : } : }
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Internet-Draft useful RATS November 2020 3130 64: SEQUENCE { 3132 3: OBJECT IDENTIFIER cRLDistributionPoints (2 5 29 31) 3137 57: OCTET STRING, encapsulates { 3139 55: SEQUENCE { 3141 53: SEQUENCE { 3143 51: [0] { 3145 49: [0] { 3147 47: [6]: 'https://android.googleapis.com/attestation/crl/' : } : } : } : } : } : } : } : } : }
3196 13: SEQUENCE { 3198 9: OBJECT IDENTIFIER: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
3209 0: NULL
: }
3211 513: BIT STRING
: 20 C8 C3 8D 4B DC A9 57 1B 46 8C 89 2F FF 72 AA : C6 F8 44 A1 1D 41 A8 F0 73 6C C3 7D 16 D6 42 6D : 8E 7E 94 07 04 4C EA 39 E6 8B 07 C1 3D BF 15 03 : DD 5C 85 BD AF B2 C0 2D 5F 6C DB 4E FA 81 27 DF : 8B 04 F1 82 77 0F C4 E7 74 5B 7F CE AA 87 12 9A : 88 01 CE 8E 9B C0 CB 96 37 9B 4D 26 A8 2D 30 FD : 9C 2F 8E ED 6D C1 BE 2F 84 B6 89 E4 D9 14 25 8B : 14 4B BA E6 24 A1 C7 06 71 13 2E 2F 06 16 A8 84 : [ Another 384 bytes skipped ] : }3728 1413: SEQUENCE { 3732 877: SEQUENCE { 3736 3: [0] { 3738 1: INTEGER 2: }
3741 10: INTEGER 03 88 26 67 60 65 89 96 85 99 3753 13: SEQUENCE { 3755 9: OBJECT IDENTIFIER: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
3766 0: NULL
: }3768 27: SEQUENCE { Richardson, et al. Expires May 6, 2021 [Page 47]
Internet-Draft useful RATS November 2020 3770 25: SET { 3772 23: SEQUENCE { 3774 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) 3779 16: PrintableString 'f92009e853b6b045': } : } : }
3797 30: SEQUENCE { 3799 13: UTCTime 20/06/2018 22:47:35 GMT 3814 13: UTCTime 17/06/2028 22:47:35 GMT: }
3829 47: SEQUENCE { 3831 25: SET { 3833 23: SEQUENCE { 3835 3: OBJECT IDENTIFIER serialNumber (2 5 4 5) 3840 16: PrintableString 'ccd18b9b608d658e': } : }
3858 18: SET { 3860 16: SEQUENCE { 3862 3: OBJECT IDENTIFIER title (2 5 4 12) 3867 9: UTF8String 'StrongBox': } : } : }
3878 546: SEQUENCE { 3882 13: SEQUENCE { 3884 9: OBJECT IDENTIFIER: rsaEncryption (1 2 840 113549 1 1 1)
3895 0: NULL
: }3897 527: BIT STRING, encapsulates { 3902 522: SEQUENCE { 3906 513: INTEGER: 00 E8 22 0B F1 72 A6 01 63 D3 3C 44 9D DB 7A 87 : D6 3D 6F 6D 92 B7 C9 4A 70 96 5D 29 7A 8E 96 3E : FE F3 10 53 B2 19 A5 BF 6E 54 AD D0 0A A2 8E 54 : E0 D4 B4 2E A6 E0 D4 30 F8 5A 47 CC 09 00 56 45 : BE DA 5A 84 59 90 18 CE 29 6C 8E 9E E6 90 98 BD : D4 D8 F8 38 82 90 C9 79 DB 31 D3 7A A1 CA BA 6A : 8B 9D 15 91 E2 6C 41 A3 2B 25 DA 4F E4 B3 14 E5 : 4B EC B7 89 06 44 18 67 C1 4C 03 35 18 D8 FD 7D : [ Another 385 bytes skipped ]
4423 3: INTEGER 65537
: } : } : }4428 182: [3] { Richardson, et al. Expires May 6, 2021 [Page 48]
Internet-Draft useful RATS November 2020 4431 179: SEQUENCE { 4434 29: SEQUENCE { 4436 3: OBJECT IDENTIFIER subjectKeyIdentifier (2 5 29 14) 4441 22: OCTET STRING, encapsulates { 4443 20: OCTET STRING: 1B 17 70 C6 97 DC 84 54 75 7C 3C 98 5C E6 1D 1D : 08 59 5D 53 : } : }
4465 31: SEQUENCE { 4467 3: OBJECT IDENTIFIER: authorityKeyIdentifier (2 5 29 35)
4472 24: OCTET STRING, encapsulates { 4474 22: SEQUENCE { 4476 20: [0]: 36 61 E1 00 7C 88 05 09 51 8B 44 6C 47 FF 1A 4C : C9 EA 4F 12 : } : } : }
4498 15: SEQUENCE { 4500 3: OBJECT IDENTIFIER basicConstraints (2 5 29 19) 4505 1: BOOLEAN TRUE 4508 5: OCTET STRING, encapsulates { 4510 3: SEQUENCE { 4512 1: BOOLEAN TRUE: } : } : }
4515 14: SEQUENCE { 4517 3: OBJECT IDENTIFIER keyUsage (2 5 29 15) 4522 1: BOOLEAN TRUE 4525 4: OCTET STRING, encapsulates { 4527 2: BIT STRING 2 unused bits: '100000'B (bit 5) : } : }
4531 80: SEQUENCE { 4533 3: OBJECT IDENTIFIER cRLDistributionPoints (2 5 29 31) 4538 73: OCTET STRING, encapsulates { 4540 71: SEQUENCE { 4542 69: SEQUENCE { 4544 67: [0] { 4546 65: [0] { 4548 63: [6]: 'https://android.googleapis.com/attestation/crl/8' : 'F6734C9FA504789' : } : } : } : } : } : } : } : } : }
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Internet-Draft useful RATS November 2020 4613 13: SEQUENCE { 4615 9: OBJECT IDENTIFIER: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
4626 0: NULL
: }
4628 513: BIT STRING
: 9B E2 2D 8C 43 AC 8F 11 35 11 77 BD F9 32 B3 01 : 8C E9 97 58 08 E5 C0 DD C4 CC A6 B1 4A A3 E5 D0 : 48 A6 18 1C 8E 5C FD 35 4A A5 12 C2 1A 82 64 3E : B4 CC 0C 0B 1F 5E D5 11 C0 B7 49 5B A6 E7 74 37 : 0B 7D 99 27 84 B7 E0 34 58 28 01 CC 03 76 50 F8 : 1A B5 3B EF CA D2 FF 7D C9 37 FE D9 F7 30 3D 31 : 24 CA 83 FD 67 AC 38 E3 82 23 B0 70 80 48 84 D6 : A1 2E 18 BD 94 1F 9A 8E 82 CC 2F EB 97 AA 5B A3 : [ Another 384 bytes skipped ] : } : }
5145 0: SET {}
: } : } : }
7.2. Windows 10 TPM
The next two sections provide two views of a CSR generated via invocation of the Certificate Enrollment Manager API similar to the below: CertificateRequestProperties request = new CertificateRequestProperties(); request.FriendlyName = "Self-Signed Device Certificate";
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request.KeyAlgorithmName = KeyAlgorithmNames.Rsa; request.KeyStorageProviderName = "Microsoft Smart Card Key Storage Provider"; request.UseExistingKey = true; request.Exportable = ExportOption.NotExportable; request.ContainerName = prj.GetContainerName();request.Subject = subject_name; request.KeyUsages = keyUsages; request.SmartcardReaderName = smartCardReaderName;
string privacyCa = "MIIDezCCAmOgAwIBAgIBATANBgkqhkiG9w0BAQsFADBUMQswCQYDVQQGEwJVUzEY" + "MBYGA1UEChMPVS5TLiBHb3Zlcm5tZW50MQ0wCwYDVQQLEwRESVNBMRwwGgYDVQQD" + "ExNQdXJlYnJlZCBQcml2YWN5IENBMB4XDTE4MDQwMzE0NTQwMFoXDTI4MDQwMzE0" + "NTQwMFowVDELMAkGA1UEBhMCVVMxGDAWBgNVBAoTD1UuUy4gR292ZXJubWVudDEN" + "MAsGA1UECxMERElTQTEcMBoGA1UEAxMTUHVyZWJyZWQgUHJpdmFjeSBDQTCCASIw" + "DQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAMROV8sQ707OSvjRxoX5S6MaB0r4" + "r5TnM97cx0RjtSVPu3O/WG9KRQdJtG9gARKKlxqgKOPJkTfTIxvUvWwKrtL9HjYs" + "IC2V/otsX3JKgPepud2CTIy3I1ADU7UD0/0MGqALbn+grDTaZOSi5p6cA0eo/f0X" + "O7UNh5r2YWOYAhZdhIy5F9BIOZEN/7pRyvKziupf3OVTQaMjMWoiDrCQC+D0xya4" + "8qxU/VFy4c9BmIg7uNzkHDqdaogo1Gsj5t2y0lW37IbRo6HrZ5Dl18laIX7s7n9k" + "Mp7GbK4rq/1FTMvI5bBpN/Pp4syi3f+oyQbSz+FPQwfBWGLukTUzPYcDVfUCAwEA" + "AaNYMFYwHQYDVR0OBBYEFAFy9PrSM65GYyC0EVDPU91WJ0BXMAsGA1UdDwQEAwIC" + "pDAoBgNVHSUEITAfBggrBgEFBQcDAgYIKwYBBQUHAwEGCSsGAQQBgjcVJDANBgkq" + "hkiG9w0BAQsFAAOCAQEAG777BuS/EXmuoHiVctA0n58u4SZb6i9Jvw1gI3qIryGM" + "2oxDSKPr36c7R2tFmAqo4m9N97wh4xFebkkYHgZWPsp0hRFy79veE+wMCw+Z0B88" + "ri4a2z/oTDmW9uf3r+BaZjRKpVoaYW9eztmz6DJA3wtvEdvUE2Nq4G1V5yXIdiSU" + "pfVd4eyEPVNy0Yp9DZDBP9vVcd5x7VfG8rzQoaDcerwrsXJ9/WLDz76A6d2/syHN" + "74CRuXYGhpBb7YL1jIhgVi6Rb4Dbq3dgDIkmTqUecEknuX73Oddr/phgqMOrVWUB" + "1XrHJbPUuC+nuPbShhJ0vPRw13TX3deqjzTsj8XEcA==";
byte[] privacyCaBytes = Convert.FromBase64String(privacyCa); IBuffer buffer = privacyCaBytes.AsBuffer(); request.AttestationCredentialCertificate = new Certificate(buffer); ;
csrToDiscard = await CertificateEnrollmentManager.UserCertificateEnrollmentManager.\ CreateRequestAsync(request);
Attestation details are described here: https://msdn.microsoft.com/ en-us/library/dn366894.aspx.
The structure is essentially a Full PKI Request as described in RFC 5272.
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* ContentInfo * SignedData* PKIData
* Empty controlSequence * One TaggestRequest
* PKCS 10
* Basic request details along with encrypted attestation extension
* Empty cmsSequence * Empty otherMsgSequence
* Certificates bag with two certs (one of which is revoked)
7.2.1. Attestation statement
This section provides an annotation attestation statement as extracted from an encrypted attestation extension. The structure of the attestation statement is defined here: https://msdn.microsoft.com/en-us/library/dn408990.aspx.600 1256: SEQUENCE { 604 9: OBJECT IDENTIFIER '1 3 6 1 4 1 311 21 24' 615 1241: SET { 619 1237: OCTET STRING : 4B 41 53 54 01 00 00 00 02 00 00 00 1C 00 00 00 : 00 00 00 00 B9 04 00 00 00 00 00 00 4B 41 44 53 : 02 00 00 00 18 00 00 00 A1 00 00 00 00 01 00 00 : 00 03 00 00 FF 54 43 47 80 17 00 22 00 0B 9A FD : AB 8A 0B E9 0B BB 3F 7F E6 B6 77 91 EF A9 15 8A : 03 B2 2B 8C BE 3F EC 56 B6 30 BF 82 73 9C 00 14 : 13 6E 2F 14 DD AF 30 72 A6 E3 89 4D BF 7A 54 26 : 36 2F 10 D6 00 00 00 00 51 4F CB E5 AD 8C 8C 60 : E6 C2 70 80 00 D4 2C 65 4C 6B 95 ED 95 00 22 00 : 0B 2B E6 2C AD 8D E8 9A 85 04 D7 F3 7B B7 4C F8 : 32 CD B4 F1 80 CA A6 35 B9 2C 39 87 B7 96 03 C3 : A3 00 22 00 0B 6C 88 60 B2 80 E3 BE 7D 34 F2 85 : DC 26 9D 1B 72 A8 0A 17 CF 31 08 F1 55 F2 9B 4E : 82 C8 5B 49 7B 1A F1 4B 12 A1 C5 D1 A4 C5 A4 59 : C4 0A 97 E0 88 ED 1C D3 B6 38 4A 5D 6C 27 F5 69 : 7D 17 AD F6 C0 03 27 09 5D 93 B5 13 EA 50 B5 05 : 27 7B A0 51 4D 1B 17 52 87 7D B8 A6 05 4A 4F 39 : CA 36 5C A1 19 19 0B 73 B4 0E 7F D3 91 DA 91 EE : 37 C6 CE 78 AF 15 21 5D EB 5E 5F 23 A7 08 E9 85 : D4 6B A0 95 6D D7 E0 3A D1 92 72 B7 D4 E5 35 6A : 01 B0 7D 35 D0 99 BA A1 77 35 76 75 E3 90 A8 8B : 86 27 B8 3D 47 75 2D 98 D0 23 4E 09 D8 26 6B 32 : 3C AB AC 50 A2 E8 FF 70 21 85 C5 5E B1 F5 9C B9 : 6E 21 27 C7 2A CD 84 61 02 47 6A A0 E1 9A 9F AF : 02 43 08 D8 BF 9F 69 14 C4 8C 80 32 2D 5C A3 60 : 48 F5 5E 8E 65 6B 5E B5 0E A4 ED B9 8B F9 C3 D9 : A8 CE C0 64 71 F6 E3 81 F7 9D 79 E5 73 7B F3 A4 : 6E 65 8D 72 B4 0A 3E 5E 70 5F AB 2B 89 B9 5E 65 : 44 BF 44 7B FB 2E 29 39 64 36 85 63 46 62 AF 25 : A5 8B 19 30 AF 50 43 50 4D 38 00 00 00 02 00 00 : 00 03 00 00 00 38 01 00 00 E0 00 00 00 00 00 00 : 00 00 00 00 00 B0 00 00 00 00 00 00 00 00 00 00 : 00 00 00 00 00 00 00 00 00 00 00 00 00 01 36 00 : 01 00 0B 00 06 00 72 00 20 9D FF CB F3 6C 38 3A : E6 99 FB 98 68 DC 6D CB 89 D7 15 38 84 BE 28 03 : 92 2C 12 41 58 BF AD 22 AE 00 10 00 10 08 00 00 : 00 00 00 01 00 9B B1 27 B7 E3 5D 0C 10 74 52 1B : 60 59 96 5E B6 08 D4 76 26 17 B5 92 49 39 34 CD : A4 2D 4D C9 3E 50 05 2E D8 9E 22 37 E2 05 D2 7F : 3B 3E 4D 9F E0 E0 31 52 74 A0 D5 18 BE F1 9F 79 : 48 D6 24 69 35 3C D4 1F 55 73 75 ED 83 D6 3A E3 : 63 77 A6 5B 92 97 86 13 7C 69 3B DE AA E5 0E 9A : 39 CF 53 DF 4C 7A E0 3C A3 EC 29 DA 18 5F 86 E6 : 22 D9 2C A3 8E D8 E2 3E 80 9C 69 52 FA 1E 90 3F : BA 09 04 D0 91 6A 27 2B 44 8C FF E8 DE FF BD B9 : CE DD 95 67 70 FD 94 E5 3A E6 E4 EA 01 A5 AC 4A : 79 5C 88 4D 07 43 C7 C0 B8 95 3E 7C 72 90 CD 35 : 99 B3 32 8A C7 8C 90 63 E3 46 88 62 35 A4 5B 54 : F1 E8 61 0E CF 85 B4 41 6F 06 94 B6 BA 6F 4B CE : F7 8A 18 6C 5E 9A 6B 65 C3 F5 58 ED 7D 6A 3A E6 : 24 B6 21 6F 8C EE 1C 21 60 9E 2F 86 22 D2 2B 8F : E0 3B 12 AC 6B F5 FF 54 C6 E8 D4 3C 2E D3 B6 8E : 7A 30 36 29 3D 00 DE 00 20 13 F5 31 2B 87 50 19 : D3 95 1F F2 B6 00 95 5B 0A E2 54 7A A0 CF 6A 2C : F5 4F AD 77 C6 D5 4F 52 CB 00 10 3B 41 34 BF D4 : FC 8B BE 87 14 47 81 4E 5C 5C 23 73 44 AF D6 56 : 6F A6 6E BE E7 63 9C 43 53 C4 3C 26 33 B6 AD 75 : 36 AC 91 98 C1 FF E3 B2 AF E6 3F 14 C0 2E 65 D7 : C1 AD F6 22 D9 59 96 B6 70 8C 30 2F DE 76 1B EB : 9D 56 C1 77 F8 1D 38 5C 7D 13 9C FD 1E 3E 00 1B : 5A 74 C4 8E 49 2B 0B B5 C5 0E E3 A7 2C 92 E2 96 : 1E 9D C8 43 02 2F 8F F8 6E 66 4A FA D8 56 57 59 : 48 A4 D5 B7 7F 49 52 CA FA 11 E4 AF 27 E7 64 21 : 76 79 9B 8A A3 1A A6 FA A1 03 3E CC CD 41 26 3C : 0D 3C DC 81 21 21 DE 92 4D 2A EF 66 DE D6 77 FE : 41 0C 5D 44 1A D0 C4 D7 8B EA 6D DE 01 EE 97 DB : 61 0F FD 62 59 00 00 00 06 00 20 8F CD 21 69 AB : 92 69 4E 0C 63 3F 1A B7 72 84 2B 82 41 BB C2 02 : 88 98 1F C7 AC 1E DD C1 FD DB 0E 00 20 E5 29 F5 : D6 11 28 72 95 4E 8E D6 60 51 17 B7 57 E2 37 C6 : E1 95 13 A9 49 FE E1 F2 04 C4 58 02 3A 00 20 AF : 2C A5 69 69 9C 43 6A 21 00 6F 1C B8 A2 75 6C 98 : BC 1C 76 5A 35 59 C5 FE 1C 3F 5E 72 28 A7 E7 00 : 20 C4 13 A8 47 B1 11 12 B1 CB DD D4 EC A4 DA AA : 15 A1 85 2C 1C 3B BA 57 46 1D 25 76 05 F3 D5 AF : 53 00 00 00 20 04 8E 9A 3A CE 08 58 3F 79 F3 44 : FF 78 5B BE A9 F0 7A C7 FA 33 25 B3 D4 9A 21 DD : 51 94 C6 58 50 : }
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The format is structured as follows:typedef struct { UINT32 Magic; UINT32 Version; UINT32 Platform; UINT32 HeaderSize; UINT32 cbIdBinding; UINT32 cbKeyAttestation; UINT32 cbAIKOpaque; BYTE idBinding[cbIdBinding]; BYTE keyAttestation[cbKeyAttestation]; BYTE aikOpaque[cbAIKOpaque];
} KeyAttestationStatement;
4B 41 53 54 - Magic 01 00 00 00 - Version 02 00 00 00 - Platform 1C 00 00 00 - HeaderSize 00 00 00 00 - cbIdBinding B9 04 00 00 - cbKeyAttestation 00 00 00 00 - cbAIKOpaque
The remainder is the keyAttestation, which is structured as follows: typedef struct { UINT32 Magic; UINT32 Platform; UINT32 HeaderSize; UINT32 cbKeyAttest; UINT32 cbSignature; UINT32 cbKeyBlob; BYTE keyAttest[cbKeyAttest]; BYTE signature[cbSignature]; BYTE keyBlob[cbKeyBlob];
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} keyAttestation;4B 41 44 53 - Magic 02 00 00 00 - Platform 18 00 00 00 - HeaderSize A1 00 00 00 - cbKeyAttest (161) 00 01 00 00 - cbSignature (256) 00 03 00 00 - cbKeyBlob
keyAttest (161 bytes) ~~~~~~~~~~~ FF 54 43 47 80 17 00 22 00 0B 9A FD AB 8A 0B E9 0B BB 3F 7F E6 B6 77 91 EF A9 15 8A 03 B2 2B 8C BE 3F EC 56 B6 30 BF 82 73 9C 00 14 13 6E 2F 14 DD AF 30 72 A6 E3 89 4D BF 7A 54 26 36 2F 10 D6 00 00 00 00 51 4F CB E5 AD 8C 8C 60 E6 C2 70 80 00 D4 2C 65 4C 6B 95 ED 95 00 22 00 0B 2B E6 2C AD 8D E8 9A 85 04 D7 F3 7B B7 4C F8 32 CD B4 F1 80 CA A6 35 B9 2C 39 87 B7 96 03 C3 A3 00 22 00 0B 6C 88 60 B2 80 E3 BE 7D 34 F2 85 DC 26 9D 1B 72 A8 0A 17 CF 31 08 F1 55 F2 9B 4E 82 C8 5B 49 7B ~~~~~~~~~~~
The keyAttest field is of type TPMS_ATTEST. The TPMS_ATTEST structure is defined in section 10.11.8 of https://trustedcomputinggroup.org/wp-content/uploads/TPM-Rev-2.0- Part-2-Structures-00.99.pdf. ~~~~~~~~~~~ FF 54 43 47 - magic 80 17 - type (TPM_ST_ATTEST_CERTIFY) 00 22 - name - TPM2B_NAME.size (34 bytes) 00 0B 9A FD AB 8A 0B E9 0B BB - TPM2B_NAME.name 3F 7F E6 B6 77 91 EF A9 15 8A 03 B2 2B 8C BE 3F EC 56 B6 30 BF 82 73 9C
00 14 - extraData - TPM2B_DATA.size (20 bytes) 13 6E 2F 14 DD AF 30 72 A6 E3 - TPM2B_DATA.buffer 89 4D BF 7A 54 26 36 2F 10 D6
00 00 00 00 51 4F CB E5 - clockInfo - TPMS_CLOCK_INFO.clock AD 8C 8C 60 - TPMS_CLOCK_INFO.resetCount E6 C2 70 80 - TPMS_CLOCK_INFO.restartCount 00 - - TPMS_CLOCK_INFO.safe
D4 2C 65 4C 6B 95 ED 95 - firmwareVersion
00 22 - attested - TPMS_CERTIFY_INFO.name.size 00 0B 2B E6 2C AD 8D E8 9A 85 - TPM2B_NAME.name 04 D7 F3 7B B7 4C F8 32 CD B4 F1 80 CA A6 35 B9 2C 39 87 B7 96 03 C3 A3 00 22 - TPMS_CERTIFY_INFO.qualifiedName.size 00 0B 6C 88 60 B2 80 E3 BE 7D - TPM2B_NAME.name 34 F2 85 DC 26 9D 1B 72 A8 0A 17 CF 31 08 F1 55 F2 9B 4E 82 C8 5B 49 7B ~~~~~~~~~~~
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Signature (256 bytes) - generated using the AIK private key ~~~~~~~~~~~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~~~~~~~~~~~The remainder is the keyBlob, which is defined here: https://github.com/Microsoft/TSS.MSR/blob/master/PCPTool.v11/inc/ TpmAtt.h.
7.3. Yubikey
As with the Android Keystore attestations, Yubikey attestations take the form of an X.509 certificate. As above, the certificate is presented here packaged along with an intermediate CA certificate as a certificates-only SignedData message.The attestations below were generated using code similar to that found in the yubico-piv-tool (https://github.com/Yubico/yubico-piv- tool). Details regarding attestations are here: https://developers.yubico.com/PIV/Introduction/PIV_attestation.html
7.3.1. Yubikey 4
0 1576: SEQUENCE { 4 9: OBJECT IDENTIFIER signedData (1 2 840 113549 1 7 2) 15 1561: [0] { 19 1557: SEQUENCE { 23 1: INTEGER 1 26 0: SET {} 28 11: SEQUENCE { 30 9: OBJECT IDENTIFIER data (1 2 840 113549 1 7 1): }
41 1533: [0] { 45 742: SEQUENCE { 49 462: SEQUENCE { 53 3: [0] { 55 1: INTEGER 2
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: }58 9: INTEGER 00 A4 85 22 AA 34 AF AE 4F 69 13: SEQUENCE { 71 9: OBJECT IDENTIFIER
: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
82 0: NULL
: }
84 43: SEQUENCE { 86 41: SET { 88 39: SEQUENCE { 90 3: OBJECT IDENTIFIER commonName (2 5 4 3) 95 32: UTF8String 'Yubico PIV Root CA Serial 263751' : } : } : } 129 32: SEQUENCE { 131 13: UTCTime 14/03/2016 00:00:00 GMT 146 15: GeneralizedTime 17/04/2052 00:00:00 GMT
: }
163 33: SEQUENCE { 165 31: SET { 167 29: SEQUENCE { 169 3: OBJECT IDENTIFIER commonName (2 5 4 3) 174 22: UTF8String 'Yubico PIV Attestation' : } : } : } 198 290: SEQUENCE { 202 13: SEQUENCE { 204 9: OBJECT IDENTIFIER
: rsaEncryption (1 2 840 113549 1 1 1)
215 0: NULL
: }
217 271: BIT STRING
: 30 82 01 0A 02 82 01 01 00 AB A9 0B 16 9B EF 31 : CC 3E AC 18 5A 2D 45 80 75 70 C7 58 B0 6C 3F 1B : 59 0D 49 B9 89 E8 6F CE BB 27 6F D8 3C 60 3A 85 : 00 EF 5C BC 40 99 3D 41 EE EA C0 81 7F 76 48 E4 : A9 4C BC D5 6B E1 1F 0A 60 93 C6 FE AA D2 8D 8E : E2 B7 CD 8B 2B F7 9B DD 5A AB 2F CF B9 0E 54 CE : EC 8D F5 5E D7 7B 91 C3 A7 56 9C DC C1 06 86 76 : 36 44 53 FB 08 25 D8 06 B9 06 8C 81 FD 63 67 CA : [ Another 142 bytes skipped ] : } 492 21: [3] { 494 19: SEQUENCE { 496 17: SEQUENCE { 498 10: OBJECT IDENTIFIER '1 3 6 1 4 1 41482 3 3' 510 3: OCTET STRING 04 03 03 : } : } : } : } 515 13: SEQUENCE { 517 9: OBJECT IDENTIFIER
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: sha256WithRSAEncryption (1 2 840 113549 1 1 11)528 0: NULL
: }
530 257: BIT STRING
: 52 80 5A 6D C3 9E DF 47 A8 F1 B2 A5 9C A3 80 81 : 3B 1D 6A EB 6A 12 62 4B 11 FD 8D 30 F1 7B FC 71 : 10 C9 B2 08 FC D1 4E 35 7F 45 F2 10 A2 52 B9 D4 : B3 02 1A 01 56 07 6B FA 64 A7 08 F0 03 FB 27 A9 : 60 8D 0D D3 AC 5A 10 CF 20 96 4E 82 BC 9D E3 37 : DA C1 4C 50 E1 3D 16 B4 CA F4 1B FF 08 64 C9 74 : 4F 2A 3A 43 E0 DE 42 79 F2 13 AE 77 A1 E2 AE 6B : DF 72 A5 B6 CE D7 4C 90 13 DF DE DB F2 8B 34 45 : [ Another 128 bytes skipped ] : } 791 783: SEQUENCE { 795 503: SEQUENCE { 799 3: [0] { 801 1: INTEGER 2
: }
804 17: INTEGER
: 00 FE B9 AF 03 3B 0B A7 79 04 02 F5 67 AE DF 72 : ED 823 13: SEQUENCE { 825 9: OBJECT IDENTIFIER
: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
836 0: NULL
: }
838 33: SEQUENCE { 840 31: SET { 842 29: SEQUENCE { 844 3: OBJECT IDENTIFIER commonName (2 5 4 3) 849 22: UTF8String 'Yubico PIV Attestation' : } : } : } 873 32: SEQUENCE { 875 13: UTCTime 14/03/2016 00:00:00 GMT 890 15: GeneralizedTime 17/04/2052 00:00:00 GMT
: }
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907 37: SEQUENCE { 909 35: SET { 911 33: SEQUENCE { 913 3: OBJECT IDENTIFIER commonName (2 5 4 3) 918 26: UTF8String 'YubiKey PIV Attestation 9e' : } : } : } 946 290: SEQUENCE { 950 13: SEQUENCE { 952 9: OBJECT IDENTIFIER: rsaEncryption (1 2 840 113549 1 1 1)
963 0: NULL
: }
965 271: BIT STRING
: 30 82 01 0A 02 82 01 01 00 93 C4 C0 35 95 7E 26 : 2A 7E A5 D0 29 C4 D7 E9 39 67 22 B1 09 45 46 4D : DB A4 77 CB 0B A3 F1 D0 69 3C 24 8D A2 72 72 27 : E1 7F DE CB 67 A4 1D D2 E5 43 44 6F 21 39 F8 57 : 34 01 0E 7E C3 81 63 63 6A 6D D7 40 20 7B AF 35 : 61 9C 8D C1 D1 2B 25 48 EE 52 FC F3 72 6A 74 96 : 01 CB 1C 1A B2 AD F9 18 96 EB 59 EF E3 3A CA BC : AA 9B 42 FE FF 60 6E 28 89 49 0D C1 B1 B0 25 AE : [ Another 142 bytes skipped ] : }
1240 60: [3] { 1242 58: SEQUENCE { 1244 17: SEQUENCE { 1246 10: OBJECT IDENTIFIER '1 3 6 1 4 1 41482 3 3' 1258 3: OCTET STRING 04 03 03 -- firmware version: }
1263 19: SEQUENCE { 1265 10: OBJECT IDENTIFIER '1 3 6 1 4 1 41482 3 7' 1277 5: OCTET STRING 02 03 4F 9B B5 -- serial number: }
1284 16: SEQUENCE { 1286 10: OBJECT IDENTIFIER '1 3 6 1 4 1 41482 3 8' 1298 2: OCTET STRING 01 01 -- PIN and touch policy: } : } : } : }
1302 13: SEQUENCE { 1304 9: OBJECT IDENTIFIER: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
1315 0: NULL
: }1317 257: BIT STRING Richardson, et al. Expires May 6, 2021 [Page 59]
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: 1F 2B B8 1C 95 A1 01 74 3F 87 27 F6 B3 A6 A9 9D : 11 B9 ED 68 92 B9 05 2D 22 36 51 28 23 3D B0 2F : 7A 17 D5 8C 0C F4 3A 68 FD 2A 34 0D 80 3C F7 8F : B8 79 B0 76 E5 4D 61 94 C5 72 D6 9F 6E 26 76 5F : 03 94 55 40 93 5C 04 EF CC 58 41 EB 7C 86 64 23 : 5F 23 5E 94 78 73 2E 77 8C 58 C5 45 87 22 CF BA : 69 06 B8 C7 06 37 10 21 8C 74 AD 08 B9 85 F2 7B : 99 02 4A 3E E8 96 09 D3 F4 C6 AB FA 49 68 E2 E0 : [ Another 128 bytes skipped ] : } : }
1578 0: SET {}
: } : } : }
7.3.2. Yubikey 5
0 1613: SEQUENCE { 4 9: OBJECT IDENTIFIER signedData (1 2 840 113549 1 7 2) 15 1598: [0] { 19 1594: SEQUENCE { 23 1: INTEGER 1 26 0: SET {} 28 11: SEQUENCE { 30 9: OBJECT IDENTIFIER data (1 2 840 113549 1 7 1): }
41 1570: [0] { 45 762: SEQUENCE { 49 482: SEQUENCE { 53 3: [0] { 55 1: INTEGER 2
: }
58 9: INTEGER 00 86 77 17 E0 1D 19 2B 26 69 13: SEQUENCE { 71 9: OBJECT IDENTIFIER
: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
82 0: NULL
: }
84 43: SEQUENCE { 86 41: SET { 88 39: SEQUENCE { 90 3: OBJECT IDENTIFIER commonName (2 5 4 3) 95 32: UTF8String 'Yubico PIV Root CA Serial 263751' : } : } : } 129 32: SEQUENCE { 131 13: UTCTime 14/03/2016 00:00:00 GMT 146 15: GeneralizedTime 17/04/2052 00:00:00 GMT
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: }163 33: SEQUENCE { 165 31: SET { 167 29: SEQUENCE { 169 3: OBJECT IDENTIFIER commonName (2 5 4 3) 174 22: UTF8String 'Yubico PIV Attestation' : } : } : } 198 290: SEQUENCE { 202 13: SEQUENCE { 204 9: OBJECT IDENTIFIER
: rsaEncryption (1 2 840 113549 1 1 1)
215 0: NULL
: }
217 271: BIT STRING
: 30 82 01 0A 02 82 01 01 00 C5 5B 8D E9 B9 3C 53 : 69 82 88 FE DA 70 FC 5C 88 78 41 25 A2 1D 7B 84 : 8E 93 36 AD 67 2B 4C AB 45 BE B2 E0 D5 9C 1B A1 : 68 D5 6B F8 63 5C 83 CB 83 38 62 B7 64 AE 83 37 : 37 8E C8 60 80 E6 01 F8 75 AA AE F6 6E A7 D5 76 : C5 C1 25 AD AA 9E 9D DC B5 7E E9 8E 2A B4 3F 99 : 0D F7 9F 20 A0 28 A0 9F B3 B1 22 5F AF 38 FB 73 : 46 F4 C7 93 30 DD FA D0 86 E0 C9 C6 72 99 AF FB : [ Another 142 bytes skipped ] : } 492 41: [3] { 494 39: SEQUENCE { 496 17: SEQUENCE { 498 10: OBJECT IDENTIFIER '1 3 6 1 4 1 41482 3 3' 510 3: OCTET STRING 05 01 02
: }
515 18: SEQUENCE { 517 3: OBJECT IDENTIFIER basicConstraints (2 5 29 19) 522 1: BOOLEAN TRUE 525 8: OCTET STRING 30 06 01 01 FF 02 01 00 : } : } : } : } 535 13: SEQUENCE { 537 9: OBJECT IDENTIFIER
: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
548 0: NULL
: }
550 257: BIT STRING
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: 05 57 B7 BF 5A 41 74 F9 5F EC 2E D2 B8 78 26 E5 : EF 4F EA BF 5A 64 C9 CF 06 7F CA 8C 0A FC 1A 47 : 1C D6 AC ED C8 5B 54 72 00 9F B8 59 AB 73 25 B2 : D6 02 A3 59 83 31 69 EE C1 5F 3D F2 2B 1B 22 CA : B6 FC F9 FB 21 32 9E 08 F3 08 54 6D C9 26 10 42 : 08 1D 3C B5 F0 5A B1 98 D4 68 DC 91 F1 D3 91 54 : 7A A0 34 8B F6 65 EB 13 9F 3A 1C BF 43 C5 D1 D0 : 33 23 C6 25 A0 4C E4 E9 AA 59 80 D8 02 1E B0 10 : [ Another 128 bytes skipped ] : } 811 800: SEQUENCE { 815 520: SEQUENCE { 819 3: [0] { 821 1: INTEGER 2: }
824 16: INTEGER
: 17 7D 2D F7 D6 6D 97 CC D6 CF 69 33 87 5B F1 5E
842 13: SEQUENCE { 844 9: OBJECT IDENTIFIER
: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
855 0: NULL
: }
857 33: SEQUENCE { 859 31: SET { 861 29: SEQUENCE { 863 3: OBJECT IDENTIFIER commonName (2 5 4 3) 868 22: UTF8String 'Yubico PIV Attestation' : } : } : } 892 32: SEQUENCE { 894 13: UTCTime 14/03/2016 00:00:00 GMT 909 15: GeneralizedTime 17/04/2052 00:00:00 GMT
: }
926 37: SEQUENCE { 928 35: SET { 930 33: SEQUENCE { 932 3: OBJECT IDENTIFIER commonName (2 5 4 3) 937 26: UTF8String 'YubiKey PIV Attestation 9e' : } : } : } 965 290: SEQUENCE { 969 13: SEQUENCE { 971 9: OBJECT IDENTIFIER
: rsaEncryption (1 2 840 113549 1 1 1)
982 0: NULL
: }
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984 271: BIT STRING: 30 82 01 0A 02 82 01 01 00 A9 02 2D 7A 4C 0B B1 : 0C 02 F9 E5 9C E5 6F 20 D1 9D F9 CE B3 B3 4D 1B : 61 B0 B4 E0 3F 44 19 72 88 8B 8D 9F 86 4A 5E C7 : 38 F0 AF C9 28 5C D8 A2 80 C9 43 93 2D FA 39 7F : E9 39 2D 18 1B A7 A2 76 8F D4 6C D0 75 96 99 0D : 06 37 9D 90 D5 71 00 6E FB 82 D1 5B 2A 7C 3B 62 : 9E AB 15 81 B9 AD 7F 3D 30 1C C2 4B 9D C4 D5 64 : 32 9A 54 D6 23 B1 65 92 A3 D7 57 E2 62 10 2B 93 : [ Another 142 bytes skipped ] : }
1259 78: [3] { 1261 76: SEQUENCE { 1263 17: SEQUENCE { 1265 10: OBJECT IDENTIFIER '1 3 6 1 4 1 41482 3 3' 1277 3: OCTET STRING 05 01 02 -- firmware version: }
1282 20: SEQUENCE { 1284 10: OBJECT IDENTIFIER '1 3 6 1 4 1 41482 3 7' 1296 6: OCTET STRING 02 04 00 93 6A A0 -- serial number: }
1304 16: SEQUENCE { 1306 10: OBJECT IDENTIFIER '1 3 6 1 4 1 41482 3 8' 1318 2: OCTET STRING 01 01 -- PIN and touch policy: }
1322 15: SEQUENCE { 1324 10: OBJECT IDENTIFIER '1 3 6 1 4 1 41482 3 9' 1336 1: OCTET STRING 02 -- form factor: } : } : } : }
1339 13: SEQUENCE { 1341 9: OBJECT IDENTIFIER: sha256WithRSAEncryption (1 2 840 113549 1 1 11)
1352 0: NULL
: }
1354 257: BIT STRING
: 9F EB 7A 4C F0 7C 67 11 ED C5 84 07 C8 19 41 B2 : 71 42 08 2B D6 CD A8 5F DC AE 79 75 6C F1 E5 4D : 28 95 89 69 9D C0 2E A7 D4 48 51 B0 75 FF 63 FD : B8 79 93 03 EA BB 8A 67 D8 E7 EC C9 1C 8E 3F AF : 74 30 D4 7E 74 A4 26 50 9F D4 57 AE 23 C0 8A 63 : 4E F3 C7 CF 5A AF 91 11 A2 6B 3B 49 24 32 26 88 : D8 4F 6F BE BC F0 2D A9 A2 88 B4 5F 54 AF 42 72 : 08 74 64 57 76 5A 02 9A 9D 21 4B FD 7F 44 8F AF : [ Another 128 bytes skipped ] : } : }
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8. Privacy Considerations.
TBD
9. Security Considerations
TBD.
10. IANA Considerations
TBD.
11. Acknowledgements
Thomas Hardjono provided the text on blockchain system. Dave Thaler suggested many small variations. Frank Xialiang suggested the scalling scenarios that might preclude a 1:1 protocol between attesters and relying parties. Henk Birkholz provided many reviews. Kathleen Moriarty provided many useful edits. Ned Smith, Anders Rundgren and Steve Hanna provided many useful pointers to TCG terms and concepts. Thomas Fossati and Shawn Willden elucidated the Android Keystore goals and limitations.12. References 12.1. Normative References[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119>.
12.2. Informative References
[android_security]Kralevich, R., "The Android Platform Security Model", n.d., <https://arxiv.org/pdf/1904.05572.pdf>.
[azureattestation]
Microsoft, ., "Azure Sphere Attestation", n.d., <https://azure.microsoft.com/enus/resources/azure-sphere- device-authentication-andattestation-service/en-us/>.
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[fido] FIDO Alliance, ., "FIDO Specification Overview", n.d.,<https://fidoalliance.org/specifications/>.
[fido_w3c]
W3C, ., "Web Authentication: An API for accessing Public Key Credentials Level 1", n.d., <https://www.w3.org/TR/webauthn-1/>.
[fidoattestation]
FIDO Alliance, ., "FIDO 2.0: Key Attestation", n.d., <https://fidoalliance.org/specs/fido-v2.0-ps-20150904/ fido-key-attestation-v2.0-ps-20150904.html>.
[fidosignature]
FIDO Alliance, ., "FIDO 2.0: Signature Format", n.d., <https://fidoalliance.org/specs/fido-v2.0-ps-20150904/ fido-signature-format-v2.0-ps-20150904.html>.
[fidotechnote]
FIDO Alliance, ., "FIDO TechNotes: The Truth about Attestation", n.d., <https://fidoalliance.org/fido- technotes-the-truth-about-attestation/>.
[I-D.birkholz-rats-tuda]
Fuchs, A., Birkholz, H., McDonald, I., and C. Bormann, "Time-Based Uni-Directional Attestation", draft-birkholz- rats-tuda-03 (work in progress), July 2020.
[I-D.fedorkow-rats-network-device-attestation]
Fedorkow, G., Voit, E., and J. Fitzgerald-McKay, "TPM- based Network Device Remote Integrity Verification", draft-fedorkow-rats-network-device-attestation-05 (work in progress), April 2020.
[I-D.gutmann-scep]
Gutmann, P., "Simple Certificate Enrolment Protocol", draft-gutmann-scep-16 (work in progress), March 2020.
[I-D.tschofenig-rats-psa-token]
Tschofenig, H., Frost, S., Brossard, M., Shaw, A., and T. Fossati, "Arm's Platform Security Architecture (PSA) Attestation Token", draft-tschofenig-rats-psa-token-05 (work in progress), March 2020.
[I-D.voit-rats-trusted-path-routing]
Voit, E., "Trusted Path Routing", draft-voit-rats-trusted- path-routing-02 (work in progress), June 2020.
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[ieee802-1AR]IEEE Standard, ., "IEEE 802.1AR Secure Device Identifier", 2009, <http://standards.ieee.org/findstds/ standard/802.1AR-2009.html>.
[intelsgx]
Intel, ., "Intel(R) Software Guard Extensions: Attestation & Provisioning Services", n.d., <https://software.intel.com/en-us/sgx/attestation- services>.
[keystore]
Google, ., "Android Keystore System", n.d., <https://developer.android.com/training/articles/ keystore>.
[keystore_attestation]
Google, ., "Verifying hardware-backed key pairs with Key Attestation", n.d., <https://developer.android.com/training/articles/security- key-attestation>.
[RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen,
"Internet X.509 Public Key Infrastructure Certificate Management Protocol (CMP)", RFC 4210, DOI 10.17487/RFC4210, September 2005, <https://www.rfc-editor.org/info/rfc4210>.
[RFC5209] Sangster, P., Khosravi, H., Mani, M., Narayan, K., and J.
Tardo, "Network Endpoint Assessment (NEA): Overview and Requirements", RFC 5209, DOI 10.17487/RFC5209, June 2008, <https://www.rfc-editor.org/info/rfc5209>.
[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
RFC 5652, DOI 10.17487/RFC5652, September 2009, <https://www.rfc-editor.org/info/rfc5652>.
[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
"Enrollment over Secure Transport", RFC 7030, DOI 10.17487/RFC7030, October 2013, <https://www.rfc-editor.org/info/rfc7030>.
[RFC8555] Barnes, R., Hoffman-Andrews, J., McCarney, D., and J.
Kasten, "Automatic Certificate Management Environment (ACME)", RFC 8555, DOI 10.17487/RFC8555, March 2019, <https://www.rfc-editor.org/info/rfc8555>.
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[SP800-147B]NIST, ., "BIOS Protection Guidelines for Servers", n.d., <https://nvlpubs.nist.gov/nistpubs/SpecialPublications/ NIST.SP.800-147B.pdf>.
[SP800-155]
NIST, ., "BIOS Integrity Measurement Guidelines (Draft)", n.d., <https://csrc.nist.gov/CSRC/media/Publications/ sp/800-155/draft/documents/draft-SP800-155_Dec2011.pdf>.
[tapinfomodel]
Group, T., "TCG Trusted Attestation Protocol (TAP) Information Model for TPM Families 1.2 and 2.0 and DICE Family 1.0", n.d., <https://trustedcomputinggroup.org/wp- content/uploads/ TNC_TAP_Information_Model_v1.00_r0.29A_publicreview.pdf>.
[tcgglossary]
Group, T., "TCG Glossary, Version 1.1", n.d., <https://trustedcomputinggroup.org/wp-content/uploads/TCG- Glossary-V1.1-Rev-1.0.pdf>.
[tpmarchspec]
Group, T., "TPM 2.0 Mobile Reference Architecture", n.d., <https://trustedcomputinggroup.org/resource/tpm-2-0- mobile-reference-architecture-specification/>.
[windowsdefender]
Microsoft, ., "Windows Defender System Guard attestation", n.d., <https://www.microsoft.com/security/blog/2018/04/19/ introducing-windows-defender-system-guard-runtime- attestation/>.
[windowshealth]
Microsoft, ., "Windows Device Health Attestation", n.d., <https://docs.microsoft.com/en-us/windowsserver/security/ device-health-attestation>.
[yubikey_attestation]
Yubico, ., "PIV Attestation", n.d., <https://developers.yubico.com/PIV/Introduction/ PIV_attestation.html>.
Appendix A. Changes
o created new section for target use caseso added comments from Guy, Jessica, Henk and Ned on TCG description.
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Authors' AddressesMichael Richardson Sandelman Software Works
Email: mcr+ietf@sandelman.ca
Carl Wallace Red Hound Software
Email: carl@redhoundsoftware.com
Wei Pan Huawei Technologies
Email: william.panwei@huawei.com
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