3.1. Record CMW

The format of the Record CMW is shown in Figure 3. The JSON [STD90] and CBOR [STD94] representations are provided separately. Both the json-record and cbor-record have the same fields, except for slight differences in the types discussed below.¶

json-record = [
  type: media-type
  value: base64url-string
  ? ind: uint .bits cm-type
]

cbor-record = [
  type: coap-content-format-type / media-type
  value: bytes
  ? ind: uint .bits cm-type
]

Each contains two or three members:¶

type:

Either a text string representing a Content-Type (e.g., an EAT media type [RFC9782]) or an unsigned integer corresponding to a CoAP Content-Format ID (Section 12.3 of [RFC7252]). The latter is not used in the JSON serialization.¶

value:

The RATS conceptual message serialized according to the value defined in the type member. When using JSON, the value field MUST be encoded as Base64 using the URL and filename-safe alphabet (Section 5 of [RFC4648]) without padding. This always applies, even if the conceptual message format is already textual (e.g., a JWT EAT). When using CBOR, the value field MUST be encoded as a CBOR byte string.¶

ind:

An optional bitmap with a maximum size of 4 bytes that indicates which conceptual message types are carried in the value field. Any combination (i.e., any value between 1 and 2³²-1 inclusive) is allowed. Only 5 bits are registered in this document, so the acceptable values are currently limited to 1 to 31. This is useful only if the type is potentially ambiguous and there is no further context available to the CMW consumer to decide. For example, this might be the case if the base media type is not profiled (e.g., application/eat+cwt), if the value field contains multiple conceptual messages with different types (e.g., both Reference Values and Endorsements within the same application/rim+cose), or if the same profile identifier is shared by different conceptual messages. The value MUST be non-zero. The absence of information about the conceptual message indicator is indicated by omitting the ind field entirely. For further details, see Section 3.1.1.¶

cm-type = &(
  reference-values: 0
  endorsements: 1
  evidence: 2
  attestation-results: 3
  appraisal-policy: 4
)

3.2. Tag CMW

Tag CMWs derive their tag numbers from a corresponding CoAP Content-Format ID using the TN() transform defined in Appendix B of [RFC9277]. Such CBOR tag numbers are in the range [1668546817, 1668612095].¶

The RATS conceptual message is first serialized according to the Content-Format ID and then encoded as a CBOR byte string, to which the TN-derived tag number is prepended.¶

The Tag CMW is defined in Figure 5 using two different macros: one for CBOR-encoded types and the other for all other types. Both macros take the CBOR tag number tn as a parameter. The tag-cm-cbor macro takes the CDDL definition of the associated conceptual message fmt as a second parameter.¶

tag-cm-cbor<tn, fmt> = #6.<tn>(bytes .cbor fmt)

tag-cm-data<tn> = #6.<tn>(bytes)

$cbor-tag /= tag-cm-cbor<1668612069, my-evidence>

my-evidence = {
  &(eat_nonce: 10) => bytes .size (8..64)
}

$cbor-tag /= tag-cm-data<1668612070>

3.3. Collection CMW

Layered Attesters and composite devices (Sections 3.2 and 3.3 of [RFC9334]) generate Evidence that consists of multiple parts. For example, in data center servers, it is not uncommon for separate attesting environments (AEs) to serve a subsection of the entire machine. One AE might measure and attest to what was booted on the main CPU, while another AE might measure and attest to what was booted on a SmartNIC plugged into a PCI Express (PCIe) slot, and a third AE might measure and attest to what was booted on the machine's Graphics Processing Unit (GPU). To allow aggregation of multiple, potentially non-homogeneous evidence formats collected from different AEs, this document defines a Collection CMW as a container that holds several CMW items, each with a label that is unique within the scope of the collection.¶

Although originally designed to support layered Attester and composite device use cases, the Collection CMW can be adapted for other scenarios that require the aggregation of RATS conceptual messages. For instance, collections may be used to group Endorsements, Reference Values, Attestation Results, and more. A single Collection CMW can contain a mix of different message types; it can also be used to carry messages related to multiple devices simultaneously.¶

The Collection CMW (Figure 6) is defined as a CBOR map or JSON object containing CMW values. The position of a cmw entry in the cmw-collection is not significant. Labels can be strings (or integers in the CBOR serialization) that serve as a mnemonic for different conceptual messages in the collection.¶

json-collection = {
  ? "__cmwc_t": ~uri / oid
  + &(label: text) => json-cmw
}

cbor-collection = {
  ? "__cmwc_t": ~uri / oid
  + &(label: (int / text)) => cbor-cmw
}

A collection MUST have at least one CMW entry.¶

The "__cmwc_t" key is reserved for associating an optional type with the overall collection and MUST NOT be used for any purpose other than described here.¶

The value of the "__cmwc_t" key is either a Uniform Resource Identifier (URI) or an object identifier (OID). The OID is always absolute and never relative. The URI MUST be in the absolute form (Section 4.3 of [RFC3986]).¶

The "__cmwc_t" key functions similarly to an EAT profile claim (see Section 4.3.2 of [RFC9711]) but at a higher level. It can be used to indicate basics like CBOR serialization and CBOR Object Signing and Encryption (COSE) algorithms just as a profile in EAT does. It provides a namespace in which the collection labels are interpreted. At the higher level, it can be used to describe the allowed Collection CMW assembly (this is somewhat parallel to the way EAT profiles indicate which claims are required and/or allowed). For an example of a "__cmwc_t" that is defined for a bundle of endorsements and reference values, see Section 4.3.1 of [CoRIM].¶

Since the Collection CMW is recursive (a Collection CMW is itself a CMW), implementations MAY limit the allowed depth of nesting.¶

3.4. Demuxing

The split in the JSON/CBOR decoding path is expected to occur via the media type or content format (see Sections 9.5 and 9.6, respectively) or via the container context of the embedded CMW (see Sections 9.1 and 9.2 for CWT/JWT and Section 9.7 for X.509).¶

The following pseudocode illustrates how a one-byte look-ahead is sufficient to determine how to decode the remaining byte buffer.¶

func exampleCMWTypeDemux(b []byte) CMWType {
  if len(b) == 0 {
    return Unknown
  }

  switch b[0] {
  case 0x82: // 2-elements cbor-record (w/o ind field)
  case 0x83: // 3-elements cbor-record (w/ ind field)
  case 0x9f: // start of cbor-record using indefinite-length encoding
    return CBORRecord
  case 0xda: // tag-cm-cbor (CBOR tag in the TN range)
    return CBORTag
  case 0x5b: // ASCII '[', start of json-record
    return JSONRecord
  case 0x7b: // ASCII '{', start of json-collection
    return JSONCollection
  case 0xa0..0xbb: // CBOR map start values, start of cbor-collection
  case 0xbf:       // ditto
    return CBORCollection
  }

  return Unknown
}

This code is provided for informational purposes only. It is not expected that implementations will follow this demuxing strategy.¶

4.1. Signing CBOR CMW Using COSE_Sign1

A CBOR CMW can be signed using COSE [RFC9052]. A signed-cbor-cmw is a COSE_Sign1 with the following layout:¶

signed-cbor-cmw = [
  protected: bytes .cbor signed-cbor-cmw-protected-hdr
  unprotected: signed-cbor-cmw-unprotected-hdr
  payload: bytes .cbor cbor-cmw
  signature: bytes
]

The payload MUST be the CBOR-encoded Tag, Record, or Collection CMW.¶

signed-cbor-cmw-protected-hdr = {
  1 => int                            ; alg
  3 => "application/cmw+cbor" / 273   ; cty
  * cose.label => cose.values
}

signed-cbor-cmw-unprotected-hdr = {
  * cose.label => cose.values
}

cose.label = int / text
cose.values = any

The protected header MUST include the signature algorithm identifier. The protected header MUST include either the media type application/cmw+cbor or the CoAP Content-Format 273. Other header parameters MAY be added to the header buckets, for example, a kid that identifies the signing key.¶

4.2. Signing JSON CMW Using JWS

A JSON CMW can be signed using JSON Web Signature (JWS) [RFC7515]. A signed-json-cmw uses either the Flattened JSON Serialization (Section 7.2.2 of [RFC7515]) or the Compact Serialization (Section 3.1 of [RFC7515]).¶

signed-json-cmw = jws-flattened-json / jws-compact

jws-flattened-json = {
  "protected": protected
  ? "header": unprotected
  "payload": payload
  "signature": signature
}

jws-compact =
  (((protected .cat ".") .cat payload) .cat ".") .cat signature

protected = text .b64u (text .json signed-json-cmw-protected-hdr)
unprotected = text .b64u (text .json signed-json-cmw-unprotected-hdr)
payload = text .b64u (text .json json-cmw)
signature = text .b64u bytes

The payload MUST be the JSON-encoded Record or Collection CMW.¶

signed-json-cmw-protected-hdr = {
  "alg": text
  "cty": "application/cmw+json"
  * text => text
}

signed-json-cmw-unprotected-hdr = {
  * text => text
}

The protected header MUST include the signature algorithm identifier and the media type application/cmw+json. Other header parameters MAY be added to the header buckets, for example, a kid that identifies the signing key.¶

4.3. Transporting CMW in COSE and JSON Web Tokens

To facilitate the embedding of CMWs in CBOR-based protocols and web APIs, this document defines two "cmw" claims for use with JWT and CWT.¶

The definitions for these claims can be found in Sections 9.2 and 9.1, respectively.¶

4.4. Transporting CMW in PKIX Formats

CMW may need to be transported in PKIX formats, such as CSRs or in X.509 certificates and CRLs.¶

The use of CMW in CSRs is documented in [RA-CERT-SIGN], while one of the possible applications in X.509 certificates and CRLs is detailed in Section 6.1 of [DICE-ARCH].¶

This section outlines the CMW extension designed to carry CMW objects. Section 7 discusses some privacy considerations related to the transport of CMW in X.509 formats.¶

The CMW extension MAY be included in X.509 certificates, CRLs [RFC5280], and CSRs.¶

The CMW extension MUST be identified by the following object identifier:¶

id-pe-cmw  OBJECT IDENTIFIER ::=
        { iso(1) identified-organization(3) dod(6) internet(1)
          security(5) mechanisms(5) pkix(7) id-pe(1) 35 }

This extension SHOULD NOT be marked critical. In cases where the wrapped conceptual message is essential for granting resource access, and there is a risk that legacy RPs would bypass crucial controls, it is acceptable to mark the extension as critical.¶

The CMW extension has the following syntax:¶

CMW ::= CHOICE {
    json UTF8String,
    cbor OCTET STRING
}

The CMW MUST include the serialized CMW object in either JSON or CBOR format, utilizing the appropriate CHOICE entry.¶

The DER-encoded [X.690] CMW is the value of the OCTET STRING for the extnValue field of the extension.¶

CMWExtn
  { iso(1) identified-organization(3) dod(6) internet(1)
    security(5) mechanisms(5) pkix(7) id-mod(0)
    id-mod-cmw-extn(123) }

DEFINITIONS IMPLICIT TAGS ::=
BEGIN

IMPORTS
  EXTENSION
  FROM PKIX-CommonTypes-2009  -- RFC 5912
    { iso(1) identified-organization(3) dod(6) internet(1)
      security(5) mechanisms(5) pkix(7) id-mod(0)
      id-mod-pkixCommon-02(57) } ;

-- CMW Extension

ext-CMW EXTENSION ::= {
  SYNTAX CMW
  IDENTIFIED BY id-pe-cmw }

-- CMW Extension OID

id-pe-cmw  OBJECT IDENTIFIER  ::=
   { iso(1) identified-organization(3) dod(6) internet(1)
     security(5) mechanisms(5) pkix(7) id-pe(1) 35 }

-- CMW Extension Syntax

CMW ::= CHOICE {
    json UTF8String,
    cbor OCTET STRING
}

END

5.1. JSON-Encoded Record

[
  "application/vnd.example.rats-conceptual-msg",
  "I0faVQ"
]

5.2. CBOR-Encoded Record

[
  64999,
  h'2347da55'
]

with the following wire representation:¶

82             # array(2)
   19 fde7     # unsigned(64999)
   44          # bytes(4)
      2347da55 # "#G\xDAU"

Note that a Media-Type-Name can also be used with the CBOR-encoded Record form, for example, if it is known that the receiver cannot handle CoAP Content-Formats, or (unlike the case in point) if a CoAP Content-Format ID has not been registered.¶

[
  "application/vnd.example.rats-conceptual-msg",
  h'2347da55'
]

5.3. CBOR-Encoded Tag CMW

1668612070(h'2347da55')

with the following wire representation:¶

da 6374ffe6    # tag(1668612070)
   44          # bytes(4)
      2347da55 # "#G\xDAU"

5.4. CBOR-Encoded Record with an Explicit Conceptual Message Indicator

This is an example of a signed CoRIM (Concise Reference Integrity Manifest) [CoRIM] with an explicit ind value of 0b0000_0011 (3), indicating that the wrapped message contains both Reference Values and Endorsements.¶

[
  "application/rim+cose",
  h'd28440a044d901f5a040',
  3
]

with the following wire representation (this example uses line wrapping per [RFC8792]):¶

=============== NOTE: '\' line wrapping per RFC 8792 ================

83                                      # array(3)
   74                                   # text(20)
      6170706c69636174696f6e2f72696d2b636f7365 # "application/rim+\
                                                                cose"
   4a                                   # bytes(10)
      d28440a044d901f5a040              # serialized CM value
   03                                   # unsigned(3)

5.5. CBOR-Encoded Collection

The following example is a CBOR-encoded Collection CMW that assembles conceptual messages from three Attesters: Evidence for Attesters A and B and Attestation Results for Attester C. It is given an explicit "__cmwc_t" using the URI form.¶

{
  "__cmwc_t": "tag:example.com,2024:composite-attester",
  / attester A / 0: [
    64999,
    h'2347da55',
    4
  ],
  / attester B / 1: 1668612070(h'2347da55'),
  / attester C / 2: [
    "application/eat+jwt",
    h'2e2e2e',
    8
  ]
}

5.6. JSON-Encoded Collection

The following example is a JSON-encoded Collection CMW that assembles Evidence from two Attesters.¶

{
  "__cmwc_t": "tag:example.com,2024:another-composite-attester",
  "attester A": [
    "application/eat-ucs+json",
    "e30K",
    4
  ],
  "attester B": [
    "application/eat-ucs+cbor",
    "oA",
    4
  ]
}

5.7. Use in JWT

The following example shows the use of the "cmw" JWT claim to transport a Collection CMW in a JWT Claims Set [RFC7519]:¶

{
  "cmw": {
    "__cmwc_t": "tag:example.com,2024:another-composite-attester",
    "attester A": [
      "application/eat-ucs+json",
      "e30K",
      4
    ],
    "attester B": [
      "application/eat-ucs+cbor",
      "oA",
      4
    ]
  },
  "iss": "evidence collection daemon",
  "exp": 1300819380
}

8.1. CMW Protection

Record, Tag, and Collection CMWs alone do not offer authenticity, integrity protection, or confidentiality. It is the responsibility of the designer for each use case to determine the necessary security properties and implement them accordingly.¶

RATS conceptual messages are typically secured using cryptography. If the messages are already protected, no additional security requirements are imposed by this encapsulation. If an adversary attempts to modify the payload encapsulation, it will result in incorrect processing of the encapsulated message, leading to an error. If the messages are not protected, additional security must be added at a different layer. For example, a cbor-record containing an Unprotected CWT Claims Set (UCCS) [RFC9781] can be signed as described in Section 4.1.¶

Section 4 describes a number of methods that can be used to add cryptographic protection to CMW.¶

8.2. Using Collection CMWs for Evidence of Composite or Layered Devices

When a Collection CMW is used to encapsulate Evidence for composite or layered attestation of a single device, all Evidence messages within the CMW MUST be cryptographically bound together to prevent an attacker from replacing Evidence from a compromised device with that from a non-compromised device. If the Collection CMW is not protected from tampering by external security measures (such as object security primitives) or internal mechanisms (such as intra-item binding), an attacker could manipulate the collection's contents to deceive the Verifier into accepting bogus Evidence as genuine.¶

Authenticity and integrity protection is expected to be provided by the underlying attestation technology. For example, key material used to sign/bind an entire Collection CMW should be an attestation key, handled as described in Section 12.1 of [RFC9334]. The binding does not necessarily have to be a signature over the Collection CMW; it might also be achieved through identifiers, linking claims (e.g., nonces) across Collection CMW items, or signing or hashing between the members of the collection. It is the responsibility of the Attester who creates the Collection CMW to ensure that the contents of the collection are integrity protected.¶

8.3. Integrating CMW into Protocols

When CMW is integrated into some hosting protocol (for example, attested CSR [RA-CERT-SIGN] or attested TLS [RA-TLS-DTLS] [RA-EXP-AUTH]), it is up to that hosting protocol to describe how CMW is intended to be used and how it fits into the overall security model.¶

Such an analysis should consider the types of conceptual messages allowed, including the permitted combinations, the protection requirements, the interface with the hosting protocol, and any other security-relevant aspect arising from the interaction between the CMW assembly and the hosting protocol.¶

9.1. CWT cmw Claim Registration

IANA has added a new cmw claim to the "CBOR Web Token (CWT) Claims" registry [IANA.cwt] as follows:¶

Claim Name:

cmw¶

Claim Description:

RATS Conceptual Message Wrapper¶

JWT Claim Name:

cmw¶

Claim Key:

299¶

Claim Value Type:

CBOR map, CBOR array, or CBOR tag¶

Change Controller:

IETF¶

Reference:

Sections 3.1, 3.2, and 3.3 of RFC 9999¶

9.2. JWT cmw Claim Registration

IANA has added a new cmw claim to the "JSON Web Token Claims" registry within the "JSON Web Token (JWT)" registry group [IANA.jwt] as follows:¶

Claim Name:

cmw¶

Claim Description:

RATS Conceptual Message Wrapper¶

Change Controller:

IETF¶

Reference:

Sections 3.1 and 3.3 of RFC 9999¶

9.3. +jws Structured Syntax Suffix

IANA has registered the +jws structured syntax suffix in the "Structured Syntax Suffixes" registry [IANA.structured-suffixes] in the manner described in [RFC6838], which can be used to indicate that the media type is encoded as JWS [RFC7515].¶

9.4. RATS Conceptual Message Wrapper (CMW) Indicators Registry

IANA has created a new "RATS Conceptual Message Wrapper (CMW) Indicators" registry within the "Remote Attestation Procedures (RATS)" registry group [IANA.rats]. The registration procedure for the new registry is IETF Review (Section 4.8 of [RFC8126]).¶

The objective is to register CMW Indicator values for all RATS conceptual messages (see Section 8 of [RFC9334]).¶

Indicator values should be added in ascending order, with no gaps between them.¶

Acceptable values correspond to the RATS conceptual messages defined by the RATS architecture [RFC9334] and any updates to it.¶

9.5. Media Types

IANA has added the following media types to the "Media Types" registry [IANA.media-types]:¶

9.6. CoAP Content-Formats

IANA has registered the following Content-Format IDs in the "CoAP Content-Formats" registry within the "Constrained RESTful Environments (CoRE) Parameters" registry group [IANA.core-parameters]:¶

$cbor-tag /= tag-cm-cbor<1668547091, cbor-collection>
$cbor-tag /= tag-cm-cbor<1668547092, signed-cbor-cmw>
$cbor-tag /= tag-cm-data<1668547093> ; bytes(cmw+json collection)
$cbor-tag /= tag-cm-data<1668547094> ; bytes(cmw+jws)

9.7. SMI Number Registration

IANA has assigned an OID for the CMW extension defined in Section 4.4 in the "SMI Security for PKIX Certificate Extension" registry within the "Structure of Management Information (SMI) Numbers (MIB Module Registrations)" registry group [IANA.smi-numbers] as follows:¶

IANA has assigned an OID for the ASN.1 module defined in Section 4.4.1 in the "SMI Security for PKIX Module Identifier" registry within the "Structure of Management Information (SMI) Numbers (MIB Module Registrations)" registry group [IANA.smi-numbers]:¶

10.1. Normative References

[IANA.core-parameters]

IANA, "Constrained RESTful Environments (CoRE) Parameters", <https://www.iana.org/assignments/core-parameters>.

[IANA.cwt]

IANA, "CBOR Web Token (CWT)", <https://www.iana.org/assignments/cwt>.

[IANA.jwt]

IANA, "JSON Web Token (JWT)", <https://www.iana.org/assignments/jwt>.

[IANA.media-types]

IANA, "Media Types", <https://www.iana.org/assignments/media-types>.

[IANA.rats]

IANA, "Remote Attestation Procedures (RATS)", <https://www.iana.org/assignments/rats>.

[IANA.smi-numbers]

IANA, "Structure of Management Information (SMI) Numbers (MIB Module Registrations)", <https://www.iana.org/assignments/smi-numbers>.

[IANA.structured-suffixes]

IANA, "Structured Syntax Suffixes", <https://www.iana.org/assignments/media-type-structured-suffix>.

[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>.

[RFC3986]

Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, DOI 10.17487/RFC3986, January 2005, <https://www.rfc-editor.org/info/rfc3986>.

[RFC4648]

Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006, <https://www.rfc-editor.org/info/rfc4648>.

[RFC5280]

Cooper, D., Santesson, S., Farrell, S., Boeyen, S., Housley, R., and W. Polk, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, <https://www.rfc-editor.org/info/rfc5280>.

[RFC5912]

Hoffman, P. and J. Schaad, "New ASN.1 Modules for the Public Key Infrastructure Using X.509 (PKIX)", RFC 5912, DOI 10.17487/RFC5912, June 2010, <https://www.rfc-editor.org/info/rfc5912>.

[RFC6268]

Schaad, J. and S. Turner, "Additional New ASN.1 Modules for the Cryptographic Message Syntax (CMS) and the Public Key Infrastructure Using X.509 (PKIX)", RFC 6268, DOI 10.17487/RFC6268, July 2011, <https://www.rfc-editor.org/info/rfc6268>.

[RFC6838]

Freed, N., Klensin, J., and T. Hansen, "Media Type Specifications and Registration Procedures", BCP 13, RFC 6838, DOI 10.17487/RFC6838, January 2013, <https://www.rfc-editor.org/info/rfc6838>.

[RFC7252]

Shelby, Z., Hartke, K., and C. Bormann, "The Constrained Application Protocol (CoAP)", RFC 7252, DOI 10.17487/RFC7252, June 2014, <https://www.rfc-editor.org/info/rfc7252>.

[RFC7515]

Jones, M., Bradley, J., and N. Sakimura, "JSON Web Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May 2015, <https://www.rfc-editor.org/info/rfc7515>.

[RFC7519]

Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015, <https://www.rfc-editor.org/info/rfc7519>.

[RFC8174]

Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>.

[RFC8610]

Birkholz, H., Vigano, C., and C. Bormann, "Concise Data Definition Language (CDDL): A Notational Convention to Express Concise Binary Object Representation (CBOR) and JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610, June 2019, <https://www.rfc-editor.org/info/rfc8610>.

[RFC9165]

Bormann, C., "Additional Control Operators for the Concise Data Definition Language (CDDL)", RFC 9165, DOI 10.17487/RFC9165, December 2021, <https://www.rfc-editor.org/info/rfc9165>.

[RFC9277]

Richardson, M. and C. Bormann, "On Stable Storage for Items in Concise Binary Object Representation (CBOR)", RFC 9277, DOI 10.17487/RFC9277, August 2022, <https://www.rfc-editor.org/info/rfc9277>.

[RFC9334]

Birkholz, H., Thaler, D., Richardson, M., Smith, N., and W. Pan, "Remote ATtestation procedureS (RATS) Architecture", RFC 9334, DOI 10.17487/RFC9334, January 2023, <https://www.rfc-editor.org/info/rfc9334>.

[RFC9741]

Bormann, C., "Concise Data Definition Language (CDDL): Additional Control Operators for the Conversion and Processing of Text", RFC 9741, DOI 10.17487/RFC9741, March 2025, <https://www.rfc-editor.org/info/rfc9741>.

[STD90]

Internet Standard 90, <https://www.rfc-editor.org/info/std90>.
At the time of writing, this STD comprises the following:

Bray, T., Ed., "The JavaScript Object Notation (JSON) Data Interchange Format", STD 90, RFC 8259, DOI 10.17487/RFC8259, December 2017, <https://www.rfc-editor.org/info/rfc8259>.

[STD94]

Internet Standard 94, <https://www.rfc-editor.org/info/std94>.
At the time of writing, this STD comprises the following:

Bormann, C. and P. Hoffman, "Concise Binary Object Representation (CBOR)", STD 94, RFC 8949, DOI 10.17487/RFC8949, December 2020, <https://www.rfc-editor.org/info/rfc8949>.

[X.680]

ITU-T, "Information technology - Abstract Syntax Notation One (ASN.1): Specification of basic notation", ITU-T Recommendation X.680, ISO/IEC 8824-1:2021, February 2021, <https://www.itu.int/rec/T-REC-X.680>.

[X.690]

ITU-T, "Information technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)", ITU-T Recommendation X.690, ISO/IEC 8825-1:2021, February 2021, <https://www.itu.int/rec/T-REC-X.690>.

10.2. Informative References

[CoRIM]

Birkholz, H., Fossati, T., Deshpande, Y., Smith, N., and W. Pan, "Concise Reference Integrity Manifest", Work in Progress, Internet-Draft, draft-ietf-rats-corim-10, 2 March 2026, <https://datatracker.ietf.org/doc/html/draft-ietf-rats-corim-10>.

[DICE-ARCH]

Trusted Computing Group, "DICE Attestation Architecture", Version 1.1, Revision 0.18, January 2024, <https://trustedcomputinggroup.org/wp-content/uploads/DICE-Attestation-Architecture-Version-1.1-Revision-18_pub.pdf>.

[EAR]

Fossati, T., Voit, E., Trofimov, S., and H. Birkholz, "EAT Attestation Results", Work in Progress, Internet-Draft, draft-ietf-rats-ear-04, 26 May 2026, <https://datatracker.ietf.org/doc/html/draft-ietf-rats-ear-04>.

[RA-CERT-SIGN]

Ounsworth, M., Tschofenig, H., Birkholz, H., Wiseman, M., and N. Smith, "Use of Remote Attestation with Certification Signing Requests", Work in Progress, Internet-Draft, draft-ietf-lamps-csr-attestation-28, 16 June 2026, <https://datatracker.ietf.org/doc/html/draft-ietf-lamps-csr-attestation-27>.

[RA-EXP-AUTH]

Sardar, M. U., Fossati, T., Reddy.K, T., Sheffer, Y., Tschofenig, H., and I. Mihalcea, "Remote Attestation with Exported Authenticators", Work in Progress, Internet-Draft, draft-fossati-seat-expat-02, 27 February 2026, <https://datatracker.ietf.org/doc/html/draft-fossati-seat-expat-02>.

[RA-TLS-DTLS]

Sheffer, Y., Mihalcea, I., Deshpande, Y., Fossati, T., and T. Reddy.K, "Using Attestation in Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)", Work in Progress, Internet-Draft, draft-fossati-seat-early-attestation-04, 27 May 2026, <https://datatracker.ietf.org/doc/html/draft-fossati-seat-early-attestation-04>.

[RFC3647]

Chokhani, S., Ford, W., Sabett, R., Merrill, C., and S. Wu, "Internet X.509 Public Key Infrastructure Certificate Policy and Certification Practices Framework", RFC 3647, DOI 10.17487/RFC3647, November 2003, <https://www.rfc-editor.org/info/rfc3647>.

[RFC8126]

Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, June 2017, <https://www.rfc-editor.org/info/rfc8126>.

[RFC8792]

Watsen, K., Auerswald, E., Farrel, A., and Q. Wu, "Handling Long Lines in Content of Internet-Drafts and RFCs", RFC 8792, DOI 10.17487/RFC8792, June 2020, <https://www.rfc-editor.org/info/rfc8792>.

[RFC9052]

Schaad, J., "CBOR Object Signing and Encryption (COSE): Structures and Process", STD 96, RFC 9052, DOI 10.17487/RFC9052, August 2022, <https://www.rfc-editor.org/info/rfc9052>.

[RFC9193]

Keränen, A. and C. Bormann, "Sensor Measurement Lists (SenML) Fields for Indicating Data Value Content-Format", RFC 9193, DOI 10.17487/RFC9193, June 2022, <https://www.rfc-editor.org/info/rfc9193>.

[RFC9711]

Lundblade, L., Mandyam, G., O'Donoghue, J., and C. Wallace, "The Entity Attestation Token (EAT)", RFC 9711, DOI 10.17487/RFC9711, April 2025, <https://www.rfc-editor.org/info/rfc9711>.

[RFC9781]

Birkholz, H., O'Donoghue, J., Cam-Winget, N., and C. Bormann, "A Concise Binary Object Representation (CBOR) Tag for Unprotected CBOR Web Token Claims Sets (UCCS)", RFC 9781, DOI 10.17487/RFC9781, May 2025, <https://www.rfc-editor.org/info/rfc9781>.

[RFC9782]

Lundblade, L., Birkholz, H., and T. Fossati, "Entity Attestation Token (EAT) Media Types", RFC 9782, DOI 10.17487/RFC9782, May 2025, <https://www.rfc-editor.org/info/rfc9782>.

[RFC9876]

Fossati, T. and E. Dijk, "Updates to the IANA Registration Procedures for Constrained Application Protocol (CoAP) Content-Formats", RFC 9876, DOI 10.17487/RFC9876, November 2025, <https://www.rfc-editor.org/info/rfc9876>.