DID Specification Registries

The interoperability registry for Decentralized Identifiers

W3C Working Group Note

More details about this document
This version:
https://www.w3.org/TR/2021/NOTE-did-spec-registries-20211102/
Latest published version:
https://www.w3.org/TR/did-spec-registries/
Latest editor's draft:
https://w3c.github.io/did-spec-registries/
History:
Publication history
Commit history
Previous version:
https://www.w3.org/TR/2021/NOTE-did-spec-registries-20211026/
Editors:
Orie Steele (Transmute)
Manu Sporny (Digital Bazaar)
Michael Prorock (mesur.io)
Authors:
Orie Steele (Transmute)
Manu Sporny (Digital Bazaar)
Feedback:
GitHub w3c/did-spec-registries (pull requests, new issue, open issues)
public-did-wg@w3.org with subject line [did-spec-registries] … message topic … (archives)
Related Documents
DID Core
DID Core Implementation Report
DID Use Cases and Requirements

Abstract

This document serves as an official registry for all known global parameters, properties, and values used by the Decentralized Identifier ecosystem.

Status of This Document

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at https://www.w3.org/TR/.

This registry is under active development and implementers are advised against using the registry unless they are directly involved with the W3C DID Working Group.

Comments regarding this document are welcome. Please file issues directly on GitHub, or send them to public-did-wg@w3.org ( subscribe, archives).

Portions of the work on this specification have been funded by the United States Department of Homeland Security's Science and Technology Directorate under contracts HSHQDC-16-R00012-H-SB2016-1-002, 70RSAT20T00000010, and HSHQDC-17-C-00019. The content of this specification does not necessarily reflect the position or the policy of the U.S. Government and no official endorsement should be inferred.

Work on this registry has also been supported by the Rebooting the Web of Trust community facilitated by Christopher Allen, Shannon Appelcline, Kiara Robles, Brian Weller, Betty Dhamers, Kaliya Young, Kim Hamilton Duffy, Manu Sporny, Drummond Reed, Joe Andrieu, and Heather Vescent, Dmitri Zagidulin, and Dan Burnett.

This document was published by the Decentralized Identifier Working Group as a Working Group Note.

GitHub Issues are preferred for discussion of this specification. Alternatively, you can send comments to our mailing list. Please send them to public-did-wg@w3.org (subscribe, archives).

Publication as a Working Group Note does not imply endorsement by the W3C Membership.

This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

This document was produced by a group operating under the W3C Patent Policy.

This document is governed by the 15 September 2020 W3C Process Document.

1. Conformance

As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.

The key words MAY, MUST, MUST NOT, and SHOULD in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

2. Introduction

This section is non-normative.

This document serves as an official registry for all known global parameters, properties, and values used by the Decentralized Identifier ecosystem.

3. The Registration Process

Software implementers might find that the existing Decentralized Identifier Core specification [DID-CORE] is not entirely capable of addressing their use case and might need to add a new parameters, properties, or values to this registry in order to achieve their use case in a globally interoperable fashion. In order to add a new parameter, property, or value to this registry, an implementer MUST submit a modification request for this registry, as a pull request on the repository where this registry is hosted, where the modification request adheres to the following policies:

  1. Any addition to the DID Core Registries MUST specify a human readable description of the addition.
  2. If there are copyright, trademark, or any intellectual property rights concerns, the addition and use MUST be authorized in writing by the intellectual property rights holder under a F/RAND license. Examples include DID Methods that use trademarked brand names, property names that utilize the titles of copyrighted works, and patented technology that would cause the use of the extension to require licensing a patent.
  3. Any addition MUST NOT create unreasonable legal, security, moral, or privacy issues that will result in direct harm to others. Examples of unacceptable additions include any containing racist language, technologies used to persecute minority populations, and unconsented pervasive tracking.
  4. Any addition to the DID Core Registries MUST link, via at least a URL, preferably a content-integrity protected one, to the defining specification so that implementers can implement the property.
  5. Any addition to the DID Core Registries that is a property or value, MUST specify a machine readable JSON-LD Context for the addition.
    • The JSON-LD Context MUST be included in full as part of the submission.
    • A namespace URI MUST be provided for the JSON-LD Context so that consumer implementations can consistently map a URI to the full context.
    • The URI provided MUST be persistent, and link all terms to their associated human readable descriptions.
    • The URI provided SHOULD resolve or link to the full context contents.
    • JSON-LD Contexts MUST be versioned and MUST NOT be date stamped.
    • JSON-LD Contexts SHOULD use scoped terms and MUST use the @protected feature to eliminate the possibility of term conflicts.
  6. Properties in the DID Core Registries MUST NOT be removed, only deprecated.

The Editors of the DID Specification Registries MUST consider all of the policies above when reviewing additions to the registry and MUST reject registry entries if they violate any of the policies in this section. Entities registering additions can challenge rejections first with the W3C DID Working Group and then, if they are not satisfied with the outcome, with the W3C Staff. W3C Staff need not be consulted on changes to the DID Specification Registries, but do have the final authority on registry contents. This is to ensure that W3C can adequately respond to time sensitive legal, privacy, security, moral, or other pressing concerns without putting an undue operational burden on W3C Staff.

Entries that are identified to cause interoperability problems MAY be marked as such at the discretion of the maintainers of this registry, and if possible, after consultation with the entry maintainer.

Any submission to the registries that meet all the criteria listed above will be accepted for inclusion. These registries enumerate all known mechanisms that meet a minimum bar, without choosing between them.

4. The Labeling Process

This section describes labels that are used to categorize registry entries.

Deprecated
This label is applied to registry entries that should not be relied on.
No Contact Info
This label is applied to registry entries for which no point of contact has been provided.

5. Property Names

The following section defines the properties available for use in a DID document. Note that some of these properties are defined in the DID Core Specification, and others are defined elsewhere and may be method- or domain-specific. Please read the associated specifications to ensure that the properties you use are appropriate for your implementation. The properties are arranged here according to the purpose they serve.

Issue

This registry is a work in progress and some properties are missing normative definitions. We are working on this! This does NOT mean that in future it will be possible to submit items to the registry without normative definitions (see § 3. The Registration Process).

5.1 DID document properties

These properties are foundational to DID documents, and are expected to be useful to all DID methods.

5.1.1 id

Normative Definition JSON-LD
DID Core DID Core
Example 1: Example of id property
{
  "id": "did:example:123",
  ...
}

5.1.2 alsoKnownAs

Normative Definition JSON-LD
DID Core DID Core
Example 2: Example of alsoKnownAs property
{
  "alsoKnownAs": "https://example.com/",
  ...
}

5.1.3 controller

Normative Definition JSON-LD
DID Core DID Core
Example 3: Example of controller property
{
  "controller": "did:example:123",
  ...
}

5.1.4 verificationMethod

Normative Definition JSON-LD
DID Core Terminology DID Core
Example 4: Example of verificationMethod property
{
  "id": "did:example:123",
  "verificationMethod": [
    {
      "id": "did:example:123#key-1",
      "type": "Ed25519VerificationKey2018",
      "controller": "did:example:123",
      "publicKeyBase58": "H3C2AVvLMv6gmMNam3uVAjZpfkcJCwDwnZn6z3wXmqPV"
    },
    {
      "id": "did:example:123#key-2",
      "type": "JsonWebKey2020",
      "controller": "did:example:123",
      "publicKeyJwk": {
        "kty": "OKP",
        "crv": "Ed25519",
        "x": "r7V8qmdFbwqSlj26eupPew1Lb22vVG5vnjhn3vwEA1Y"
      },
    }
  ]
}

5.1.5 publicKey

Deprecated

This property has been deprecated, use verificationMethod instead.

Normative Definition JSON-LD
security-vocab security-vocab context
Example 5: Example of publicKey property
{
  "id": "did:example:123",
  "publicKey": [
    {
      "id": "did:example:123#ZC2jXTO6t4R501bfCXv3RxarZyUbdP2w_psLwMuY6ec",
      "type": "Ed25519VerificationKey2018",
      "controller": "did:example:123",
      "publicKeyBase58": "H3C2AVvLMv6gmMNam3uVAjZpfkcJCwDwnZn6z3wXmqPV"
    },
    {
      "id": "did:example:123#WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q",
      "type": "EcdsaSecp256k1VerificationKey2019",
      "controller": "did:example:123",
      "publicKeyJwk": {
        "crv": "secp256k1",
        "x": "NtngWpJUr-rlNNbs0u-Aa8e16OwSJu6UiFf0Rdo1oJ4",
        "y": "qN1jKupJlFsPFc1UkWinqljv4YE0mq_Ickwnjgasvmo",
        "kty": "EC",
        "kid": "WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q"
      }
    }
  ]
}

5.1.6 service

Normative Definition JSON-LD
DID Core DID Core
Example 6: Example of service and serviceEndpoint properties
{
  ...
  "service": [{
    "id": "did:example:123#edv",
    "type": "EncryptedDataVault",
    "serviceEndpoint": "https://edv.example.com/"
  }]
}

5.2 Verification relationships

These are properties that express the relationship between the DID subject and a verification method using a verification relationship.

5.2.1 assertionMethod

Normative Definition JSON-LD
DID Core DID Core
Example 7: Example of assertionMethod property
{
  ...
  "publicKey": [{
    "id": "did:example:123#WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q",
    "type": "EcdsaSecp256k1VerificationKey2019",
    "controller": "did:example:123",
    "publicKeyJwk": {
      "crv": "secp256k1",
      "x": "NtngWpJUr-rlNNbs0u-Aa8e16OwSJu6UiFf0Rdo1oJ4",
      "y": "qN1jKupJlFsPFc1UkWinqljv4YE0mq_Ickwnjgasvmo",
      "kty": "EC",
      "kid": "WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q"
    }
  }],
  "assertionMethod": [{
    "id": "did:example:123#z6MkpzW2izkFjNwMBwwvKqmELaQcH8t54QL5xmBdJg9Xh1y4",
    "type": "Ed25519VerificationKey2018",
    "controller": "did:example:123",
    "publicKeyBase58": "BYEz8kVpPqSt5T7DeGoPVUrcTZcDeX5jGkGhUQBWmoBg"
  },
  "did:example:123#WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q"
  ]
}

5.2.2 authentication

Normative Definition JSON-LD
DID Core DID Core
Example 8: Example of authentication property
{
  ...
  "publicKey": [{
    "id": "did:example:123#WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q",
    "type": "EcdsaSecp256k1VerificationKey2019",
    "controller": "did:example:123",
    "publicKeyJwk": {
      "crv": "secp256k1",
      "x": "NtngWpJUr-rlNNbs0u-Aa8e16OwSJu6UiFf0Rdo1oJ4",
      "y": "qN1jKupJlFsPFc1UkWinqljv4YE0mq_Ickwnjgasvmo",
      "kty": "EC",
      "kid": "WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q"
    }
  }],
  "authentication": [{
    "id": "did:example:123#z6MkpzW2izkFjNwMBwwvKqmELaQcH8t54QL5xmBdJg9Xh1y4",
    "type": "Ed25519VerificationKey2018",
    "controller": "did:example:123",
    "publicKeyBase58": "BYEz8kVpPqSt5T7DeGoPVUrcTZcDeX5jGkGhUQBWmoBg"
  },
  "did:example:123#WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q"
  ]
}

5.2.3 capabilityDelegation

Normative Definition JSON-LD
DID Core DID Core
Example 9: Example of capabilityDelegation property
{
  ...
  "publicKey": [{
    "id": "did:example:123#WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q",
    "type": "EcdsaSecp256k1VerificationKey2019",
    "controller": "did:example:123",
    "publicKeyJwk": {
      "crv": "secp256k1",
      "x": "NtngWpJUr-rlNNbs0u-Aa8e16OwSJu6UiFf0Rdo1oJ4",
      "y": "qN1jKupJlFsPFc1UkWinqljv4YE0mq_Ickwnjgasvmo",
      "kty": "EC",
      "kid": "WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q"
    }
  }],
  "capabilityDelegation": [{
    "id": "did:example:123#z6MkpzW2izkFjNwMBwwvKqmELaQcH8t54QL5xmBdJg9Xh1y4",
    "type": "Ed25519VerificationKey2020",
    "controller": "did:example:123",
    "publicKeyMultibase": "z6MkpzW2izkFjNwMBwwvKqmELaQcH8t54QL5xmBdJg9Xh1y4"
  },
  "did:example:123#WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q"
  ]
}

5.2.4 capabilityInvocation

Normative Definition JSON-LD
DID Core DID Core
Example 10: Example of capabilityInvocation property
{
  ...
  "publicKey": [{
    "id": "did:example:123#WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q",
    "type": "EcdsaSecp256k1VerificationKey2019",
    "controller": "did:example:123",
    "publicKeyJwk": {
      "crv": "secp256k1",
      "x": "NtngWpJUr-rlNNbs0u-Aa8e16OwSJu6UiFf0Rdo1oJ4",
      "y": "qN1jKupJlFsPFc1UkWinqljv4YE0mq_Ickwnjgasvmo",
      "kty": "EC",
      "kid": "WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q"
    }
  }],
  "capabilityInvocation": [{
    "id": "did:example:123#z6MkpzW2izkFjNwMBwwvKqmELaQcH8t54QL5xmBdJg9Xh1y4",
    "type": "Ed25519VerificationKey2020",
    "controller": "did:example:123",
    "publicKeyMultibase": "z6MkpzW2izkFjNwMBwwvKqmELaQcH8t54QL5xmBdJg9Xh1y4"
  },
  "did:example:123#WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q"
  ]
}

5.2.5 keyAgreement

Normative Definition JSON-LD
DID Core DID Core
Example 11: Example of keyAgreement property
{
  ...
  "keyAgreement": [
    {
      "id": "did:example:123#zC9ByQ8aJs8vrNXyDhPHHNNMSHPcaSgNpjjsBYpMMjsTdS",
      "type": "X25519KeyAgreementKey2019",
      "controller": "did:example:123",
      "publicKeyMultibase": "zC9ByQ8aJs8vrNXyDhPHHNNMSHPcaSgNpjjsBYpMMjsTdS"
    }
  ]
}

5.3 Verification method properties

These properties are for use on a verification method object, in the value of verificationMethod.

5.3.1 publicKeyJwk

Normative Definition JSON-LD
security-vocab DID Core
Example 12: Example of publicKeyJwk property
{
  "id": "did:example:123#_Qq0UL2Fq651Q0Fjd6TvnYE-faHiOpRlPVQcY_-tA4A",
  "type": "JsonWebKey2020",
  "controller": "did:example:123",
  "publicKeyJwk": {
    "crv": "Ed25519",
    "x": "VCpo2LMLhn6iWku8MKvSLg2ZAoC-nlOyPVQaO3FxVeQ",
    "kty": "OKP",
    "kid": "_Qq0UL2Fq651Q0Fjd6TvnYE-faHiOpRlPVQcY_-tA4A"
  }
},

5.3.2 publicKeyBase58

Normative Definition JSON-LD
security-vocab DID Core

5.3.3 publicKeyHex

Normative Definition JSON-LD
security-vocab security-vocab/v3-unstable
Example 13: Example of publicKeyHex property
{
  "@context":[
    "https://www.w3.org/ns/did/v1",
    "https://identity.foundation/EcdsaSecp256k1RecoverySignature2020#"
  ],
  "id":"did:example:123",
  "publicKey":[{
    "id": "did:example:123#vm-2",
    "controller": "did:example:123",
    "type": "EcdsaSecp256k1RecoveryMethod2020",
    "publicKeyHex": "027560af3387d375e3342a6968179ef3c6d04f5d33b2b611cf326d4708badd7770"
  }]
}

5.3.4 publicKeyMultibase

Normative Definition JSON-LD
security-vocab DID Core

5.3.5 blockchainAccountId

Normative Definition JSON-LD
security-vocab https://w3id.org/security/suites/secp256k1-2020
Example 14: Example of blockchainAccountId property
{
  "@context":[
    "https://www.w3.org/ns/did/v1",
    "https://identity.foundation/EcdsaSecp256k1RecoverySignature2020#"
  ],
  "id":"did:example:123",
  "publicKey":[{
    "id": "did:example:123#vm-3",
    "controller": "did:example:123",
    "type": "EcdsaSecp256k1RecoveryMethod2020",
    "blockchainAccountId":"eip155:1:0xab16a96d359ec26a11e2c2b3d8f8b8942d5bfcdb"
  }]
}

5.3.6 ethereumAddress

This property is deprecated in favor of blockchainAccountId.
Normative Definition JSON-LD
security-vocab security-vocab-v3-unstable
Example 15: Example of ethereumAddress property
{
  "@context":[
    "https://www.w3.org/ns/did/v1",
    "https://identity.foundation/EcdsaSecp256k1RecoverySignature2020#"
  ],
  "id":"did:example:123",
  "publicKey":[{
    "id": "did:example:123#vm-3",
    "controller": "did:example:123",
    "type": "EcdsaSecp256k1RecoveryMethod2020",
    "ethereumAddress": "0xF3beAC30C498D9E26865F34fCAa57dBB935b0D74"
  }]
}

5.4 Service properties

These properties are for use on a service object, in the value of service.

5.4.1 serviceEndpoint

Normative Definition JSON-LD
DID Core DID Core
Example 16: Example of service and serviceEndpoint properties
{
  ...
  "service": [{
    "id": "did:example:123#edv",
    "type": "EncryptedDataVault",
    "serviceEndpoint": "https://edv.example.com/"
  }]
}

6. Property Values

6.1 Verification method types

These are values to be used for the type in a verification method object.

6.1.1 JsonWebKey2020

Issue

ISSUE 240 on DID Core: The duplication and/or possible interaction of properties held in a JWK and a verification method are an active topic of discussion in the Working Group. Implementers are cautioned that the behavior of values associated with this property are not stable and might change in the future.

Do not include private or extraneous information in verification methods. The class of private information related to JWKs is defined here.

Normative Definition JSON-LD
JSON Web Signature 2020 DID Core
Example 17: Example of JsonWebKey2020 class
{
  "id": "did:example:123#_TKzHv2jFIyvdTGF1Dsgwngfdg3SH6TpDv0Ta1aOEkw",
  "type": "JsonWebKey2020",
  "controller": "did:example:123",
  "publicKeyJwk": {
    "crv": "P-256",
    "x": "38M1FDts7Oea7urmseiugGW7tWc3mLpJh6rKe7xINZ8",
    "y": "nDQW6XZ7b_u2Sy9slofYLlG03sOEoug3I0aAPQ0exs4",
    "kty": "EC",
    "kid": "_TKzHv2jFIyvdTGF1Dsgwngfdg3SH6TpDv0Ta1aOEkw"
  }
}

6.1.2 EcdsaSecp256k1VerificationKey2019

Normative Definition JSON-LD
Ecdsa Secp256k1 Signature 2019 DID Core
Example 18: Example of EcdsaSecp256k1VerificationKey2019 class
{
  "id": "did:example:123#WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q",
  "type": "EcdsaSecp256k1VerificationKey2019",
  "controller": "did:example:123",
  "publicKeyJwk": {
    "crv": "secp256k1",
    "x": "NtngWpJUr-rlNNbs0u-Aa8e16OwSJu6UiFf0Rdo1oJ4",
    "y": "qN1jKupJlFsPFc1UkWinqljv4YE0mq_Ickwnjgasvmo",
    "kty": "EC",
    "kid": "WjKgJV7VRw3hmgU6--4v15c0Aewbcvat1BsRFTIqa5Q"
  }
}

6.1.3 Ed25519VerificationKey2018

Normative Definition JSON-LD
Ed25519 Signature 2018 DID Core
Example 19: Example of Ed25519VerificationKey2018 class
{
  "id": "did:example:123#ZC2jXTO6t4R501bfCXv3RxarZyUbdP2w_psLwMuY6ec",
  "type": "Ed25519VerificationKey2018",
  "controller": "did:example:123",
  "publicKeyBase58": "H3C2AVvLMv6gmMNam3uVAjZpfkcJCwDwnZn6z3wXmqPV"
}

6.1.4 Bls12381G1Key2020

Normative Definition JSON-LD
BBS+ Signatures 2020 DID Core
Example 20: Example of Bls12381G1Key2020 class
{
  "id": "did:example:123#z3tEGVtEKzdhJB2rT5hLVjwQPis8k7bTM16t7vDZrQaoddk6wZ7or6xPPs1P8H9U16Xe75",
  "type": "Bls12381G1Key2020",
  "controller": "did:example:123",
  "publicKeyBase58": "7bXhTVonHPizXP72AE92PPmRiaXipC519yU7F6NxUFExWpyQo57LuKKBoTyuZ3uWm9",
}

6.1.5 Bls12381G2Key2020

Normative Definition JSON-LD
BBS+ Signatures 2020 DID Core
Example 21: Example of Bls12382G2Key2020 class
{
  "id": "did:example:123#zUC7K51WYEsj8y6KPVa1XfwdW5ZJrW5kSbMV619j128T6atCLLXJjjovMZsJ3Ay4STdngRkvM4ygT4qm1mk6HR8FvipSY435nLgYS1TTcaqJAzDWzM1iB9vh3hTL1DEKitwn56i",
  "type": "Bls12381G2Key2020",
  "controller": "did:example:123",
  "publicKeyBase58": "25ETdUZDVnME6yYuAMjFRCnCPcDmYQcoZDcZuXAfeMhXPvjZg35QmZ7uctBcovA69YDM3Jf7s5BHo4u1y89nY6mHiji8yphZ4AMm4iNCRh35edSg76Dkasu3MY2VS9LnuaVQ",

}

6.1.6 PgpVerificationKey2021

Normative Definition JSON-LD
Linked Data Signatures for PGP https://w3id.org/security/suites/pgp-2021/v1 Use of this verification key should be in line with the OpenPGP Message Format as defined in RFC 4880
{
  "@context":[
    "https://www.w3.org/ns/did/v1",
    "https://gpg.jsld.org/contexts/lds-gpg2020-v0.0.jsonld"
  ],
  "id":"did:example:123",
  "publicKey":[{
    "id": "did:example:123#989ed1057a294c8a3665add842e784c4d08de1e2",
    "type": "PgpVerificationKey2021",
    "controller": "did:example:123",
    "publicKeyPgp": "-----BEGIN PGP PUBLIC KEY BLOCK-----\r\nVersion: OpenPGP.js v4.9.0\r\nComment: https://openpgpjs.org\r\n\r\nxjMEXkm5LRYJKwYBBAHaRw8BAQdASmfrjYr7vrjwHNiBsdcImK397Vc3t4BL\r\nE8rnN......v6\r\nDw==\r\n=wSoi\r\n-----END PGP PUBLIC KEY BLOCK-----\r\n"
  }]
}

6.1.7 RsaVerificationKey2018

Normative Definition JSON-LD
RSA Signature Suite 2018 DID Core
{
  "id": "did:example:123#key-0",
  "type": "RsaVerificationKey2018",
  "controller": "did:example:123",
  "publicKeyJwk": {
    "kty":"RSA",
    "e":"AQAB",
    "use":"sig",
    "kid":"tNksV42EUs3Xct9AkgZyFWglItRGMxVZ1A1XM68SNq0
    "n":"kO2d_qQTEBjYFGcoY_da7ziFY4L2QX14K7snCee09n-cY2eP-oJXk8T2_lL20YnpYhf4i
    jhkWHGU8kY8-FWPRrzSeu3JUMVSZoqTgoAiKWdnSLNvPVxvGuD2CiA3T6AkwUC03D2AkOLCcJV
    8h_hxUEPeDawF7ArpuJW5DXzEJjE7gOjN4r6d7VB6sd5y-3la54H2ADz2amHLdBWs30fL4BRBH
    lVdx0YmF37V4u5yvnnb5Iyr3kBXJes8t0MUMPkjqEEXRmukpKUzZYNpWDXY0tVcXeK5sRx0DAn
    lNgNNf14-vsyjGkj2Rz0oGW73jjWa8dw-yVlDEHyIkQU9-UY4dFXbVjdIO8j_5ghh62o1T7Y4w
    5CWMc-FxPE3LHe-_teW97X__NN-ToYgfi42IvV2mYOdQMCbvnvY2oMdK3b9wmeVi0marToauL5
    LMg5xHDKopmIR7E3VyRtNYwDFAZ89kadcbSrZ8zTR5APaB7Tmp2L2ZfXKxqKQuxlFTTCcZtg4e
    5AN8QuYdI18DEDQn2umUU_Twj7k4CXvuIKVL8p4yRHC4CHAGIm9cH_t11dF3wXygaENVOGRXQu
    0g1iKq0mO2rWpOqkGJ5uXMFb5lx54i8uOjCdZ9y2el28xA55Ve95KCxeTHp997Bn3TIgbeQ-B_
    -3PBVTuuAAH8y9fFNKtu5E"
  }
}

6.1.8 X25519KeyAgreementKey2019

Issue 164: X25519KeyAgreementKey2019 has no normative definition

Normative definition in a suite is required for registration, this entry should be updated or removed.

Normative Definition JSON-LD
Normative definition pending DID Core
Example 24: Example of X25519KeyAgreementKey2019
{
  ...
  "keyAgreement": [
    {
      "id": "did:example:123#zC9ByQ8aJs8vrNXyDhPHHNNMSHPcaSgNpjjsBYpMMjsTdS",
      "type": "X25519KeyAgreementKey2019",
      "controller": "did:example:123",
      "publicKeyBase58": "9hFgmPVfmBZwRvFEyniQDBkz9LmV7gDEqytWyGZLmDXE"
    }
  ]
}

6.1.9 SchnorrSecp256k1VerificationKey2019

Normative Definition JSON-LD
security-vocab Link is to a placeholder! Definition pending DID Core

6.1.10 EcdsaSecp256k1RecoveryMethod2020

Normative Definition JSON-LD
Ecdsa Secp256k1 Recovery Signature 2020 lds-ecdsa-secp256k1-recovery2020-0.0.jsonld
{
  "@context": [
    "https://www.w3.org/ns/did/v1",
    "https://identity.foundation/EcdsaSecp256k1RecoverySignature2020#"
  ],
  "id":"did:example:123",
  "publicKey": [
    {
      "id": "did:example:123#vm-1",
      "controller": "did:example:123",
      "type": "EcdsaSecp256k1RecoveryMethod2020",
      "publicKeyJwk": {
        "crv": "secp256k1",
        "kid": "JUvpllMEYUZ2joO59UNui_XYDqxVqiFLLAJ8klWuPBw",
        "kty": "EC",
        "x": "dWCvM4fTdeM0KmloF57zxtBPXTOythHPMm1HCLrdd3A",
        "y": "36uMVGM7hnw-N6GnjFcihWE3SkrhMLzzLCdPMXPEXlA"
      }
    },
    {
      "id": "did:example:123#vm-2",
      "controller": "did:example:123",
      "type": "EcdsaSecp256k1RecoveryMethod2020",
      "publicKeyHex": "027560af3387d375e3342a6968179ef3c6d04f5d33b2b611cf326d4708badd7770"
    },
    {
      "id": "did:example:123#vm-3",
      "controller": "did:example:123",
      "type": "EcdsaSecp256k1RecoveryMethod2020",
      "ethereumAddress": "0xF3beAC30C498D9E26865F34fCAa57dBB935b0D74"
    }
  ]
}

6.1.11 VerifiableCondition2021

Normative Definition JSON-LD
Verifiable Condition 2021 verifiable-conditions-2021-v1.json
{
    "id": "did:example:123#1",
    "controller": "did:example:123",
    "type": "VerifiableCondition2021",
    "conditionAnd": [{
        "id": "did:example:123#1-1",
        "controller": "did:example:123",
        "type": "VerifiableCondition2021",
        "conditionOr": [{
            "id": "did:example:123#1-1-1",
            "controller": "did:example:123",
            "type": "EcdsaSecp256k1VerificationKey2019",
            "publicKeyBase58": "5JBxKqYKzzoHrzeqwp6zXk8wZU3Ah94ChWAinSj1fYmyJvJS5rT"
        }, {
            "id": "did:example:123#1-1-2",
            "controller": "did:example:123",
            "type": "Ed25519VerificationKey2018",
            "publicKeyBase58": "PZ8Tyr4Nx8MHsRAGMpZmZ6TWY63dXWSCzamP7YTHkZc78MJgqWsAy"
        }]
    }, {
        "id": "did:example:123#1-2",
        "controller": "did:example:123",
        "type": "Ed25519VerificationKey2018",
        "publicKeyBase58": "H3C2AVvLMv6gmMNam3uVAjZpfkcJCwDwnZn6z3wXmqPV"
    }]
}

6.2 Service types

These are values to be used for the type property in a service object.

6.2.1 LinkedDomains

Issue 167: LinkedDomains IRI is not stable

https://identity.foundation/.well-known/resources/did-configuration/#LinkedDomains

^ if this link changes the term defintion registered in did core will need to change, we should be sure we like this URL as is... forever.

Normative Definition JSON-LD
Well Known DID Configuration Well Known DID Configuration
Example 27: Example of service and serviceEndpoint properties
{
  "@context": ["https://www.w3.org/ns/did/v1","https://identity.foundation/.well-known/did-configuration/v1"],
  "id": "did:example:123",
  "verificationMethod": [{
    "id": "did:example:123#456",
    "type": "JsonWebKey2020",
    "controller": "did:example:123",
    "publicKeyJwk": {
      "kty": "OKP",
      "crv": "Ed25519",
      "x": "VCpo2LMLhn6iWku8MKvSLg2ZAoC-nlOyPVQaO3FxVeQ"
    }
  }],
  "service": [
    {
      "id":"did:example:123#foo",
      "type": "LinkedDomains",
      "serviceEndpoint": {
        "origins": ["https://foo.example.com", "https://identity.foundation"]
      }
    },
    {
      "id":"did:example:123#bar",
      "type": "LinkedDomains",
      "serviceEndpoint": "https://bar.example.com"
    }
  ]
}

6.2.2 DIDCommMessaging

Normative Definition JSON-LD
DIDComm Messaging DIDComm Messaging
Example 28: Example of service and serviceEndpoint properties
{
  "@context":[
      "https://www.w3.org/ns/did/v1",
      "https://didcomm.org/messaging/contexts/v2"
  ],
  ...
  "type":"DIDCommMessaging",
  "serviceEndpoint":"http://example.com/path",
  "accept":[
      "didcomm/v2",
      "didcomm/aip2;env=rfc587"
  ],
  "routingKeys":[
      "did:example:somemediator#somekey"
  ]
  ...
}

7. Representations

This table provides a reference for media types and the associated specifications for producing and consuming those representations.

Media Type Specification
application/did+json DID Core
application/did+ld+json DID Core
application/did+cbor The Plain CBOR Representation

8. Representation-Specific Entries

8.1 JSON

These are entries in DID documents that are specific to the JSON representation.

(No entries yet)

8.2 JSON-LD

These are entries in DID documents that are specific to the JSON-LD representation.

8.2.1 @context

Normative Definition
DID Core

The following values are acceptable values for the @context entry as a JSON String or first item of a JSON Array, represented as a JSON String.

@context Values Specification Version
https://www.w3.org/ns/did/v1 DID Core 1.0 Working draft
Example 29: Example of @context in the JSON-LD representation
{
  "@context": [
    "https://www.w3.org/ns/did/v1",
    "https://example.com/blockchain-identity/v1"
  ],
  ...
}

8.3 CBOR

These are entries in DID documents that are specific to the CBOR representation.

(No entries yet)

9. DID Resolution Input Metadata

These properties contain information pertaining to the DID resolution request.

9.1 accept

Normative Definition
DID Core
Example 30: Example of accept metadata property
{
  "accept": "application/did+ld+json"
}

10. DID Resolution Metadata

These properties contain information pertaining to the DID resolution response.

10.1 contentType

Normative Definition
DID Core
Example 31: Example of contentType metadata property
{
  "contentType": "application/did+ld+json"
}

10.2 error

Normative Definition
DID Core
Example 32: Example of error metadata property
{
  "error": "notFound"
}

10.2.1 invalidDid

Normative Definition
DID Core
Example 33: Example of invalidDid error value
{
  "error": "invalidDid"
}

10.2.2 invalidDidUrl

Normative Definition
DID Core
Example 34: Example of invalidDidUrl error value
{
  "error": "invalidDidUrl"
}

10.2.3 notFound

Normative Definition
DID Core
Example 35: Example of notFound error value
{
  "error": "notFound"
}

10.2.4 representationNotSupported

Normative Definition
DID Core
Example 36: Example of representationNotSupported error value
{
  "error": "representationNotSupported"
}

11. DID Document Metadata

These properties contain information pertaining to the DID document itself, rather than the DID subject.

11.1 created

Issue

See DID Core #203.

Normative Definition JSON-LD
DID Core DID Core
Example 37: Example of created property
{
  "created": "2019-03-23T06:35:22Z"
}

11.2 updated

Issue

See DID Core #203.

Normative Definition JSON-LD
DID Core DID Core
Example 38: Example of updated property
{
  "updated": "2023-08-10T13:40:06Z"
}

11.3 deactivated

Normative Definition JSON-LD
DID Core DID Core
Example 39: Example of deactivated property
{
  "deactivated": true
}

11.4 nextUpdate

Normative Definition JSON-LD
DID Core DID Core
Example 40: Example of nextUpdate property
{
  "nextUpdate": "2023-08-10T13:40:06Z"
}

11.5 versionId

Normative Definition JSON-LD
DID Core DID Core
Example 41: Example of versionId property
{
  "versionId": "bafyreifederejlobaec6kwpl2mc3tw7qk3j3ey4uytkbiw2qw7dzylud6i"
}

11.6 nextVersionId

Normative Definition JSON-LD
DID Core DID Core
Example 42: Example of nextVersionId property
{
  "nextVersionId": "bafyreifederejlobaec6kwpl2mc3tw7qk3j3ey4uytkbiw2qw7dzylud6i"
}

11.7 equivalentId

Normative Definition JSON-LD
DID Core DID Core
Example 43: Example of equivalentId property
{
  "equivalentId": ["did:example:ABC", "did:example:Abc"]
}

11.8 canonicalId

Normative Definition JSON-LD
DID Core DID Core
Example 44: Example of canonicalId property
{
  "canonicalId": "did:example:ABC"
}

12. Parameters

12.1 hl

Normative Definition
DID Core
Example 45: Example of hl parameter
did:example:123?hl=zQmWvQxTqbG2Z9HPJgG57jjwR154cKhbtJenbyYTWkjgF3e

12.2 service

Normative Definition
DID Core
Example 46: Example of service parameter
did:example:123?service=agent

12.3 versionId

Normative Definition
DID Core
Example 47: Example of versionId parameter
did:example:123?versionId=4

12.4 versionTime

Normative Definition
DID Core
Example 48: Example of versionTime parameter
did:example:123?versionTime=2016-10-17T02:41:00Z

12.5 relativeRef

Normative Definition
DID Core
Example 49: Example of relativeRef parameter
did:example:123?service=files&relativeRef=%2Fmyresume%2Fdoc%3Fversion%3Dlatest%23intro

12.6 initialState

Normative Definition
DID Spec Extensions by DIF
Example 50: Example of initialState parameter
did:example:123?initialState=eyJkZWx0YV9oYXNoIjoiRWlDUlRKZ2Q0U0V2YUZDLW9fNUZjQnZJUkRtWF94Z3RLX3g...

12.7 transformKeys

Normative Definition
DID Spec Extensions by DIF
Example 51: Example of transformKeys parameter
did:example:123?transformKeys=jwk

12.8 signedIetfJsonPatch

Normative Definition
DID Spec Extensions by DIF
Example 52: Example of signedIetfJsonPatch parameter
did:example:123?signedIetfJsonPatch=eyJraWQiOiJkaWQ6ZXhhbXBsZTo0NTYjX1FxMFVMMkZxNjUxUTBGamQ2VH...

12.9 resource

Normative Definition
DID URL Resource Parameter Specification
Example 53: A DID URL with a 'resource' DID parameter
did:foo:21tDAKCERh95uGgKbJNHYp?resource=true

13. DID Methods

This table summarizes the DID method specifications currently in development. The links will be updated as subsequent Implementer’s Drafts are produced.

The normative requirements for DID method specifications can be found in Decentralized Identifiers v1.0: Methods [DID-CORE]. DID methods that do not meet these requirements will not be accepted. We encourage DID method authors to provide an email address in the Author Links column, as this helps with maintenance. If an email address is omitted, a label noting that there is no contact information for the author will be applied to the registry entry.

Method Name Status DLT or Network Author Links Link
did:3: PROVISIONAL Ceramic Network Joel Thorstensson 3ID DID Method
did:abt: PROVISIONAL ABT Network ArcBlock ABT DID Method
did:aergo: PROVISIONAL Aergo Blocko Aergo DID Method
did:ala: PROVISIONAL Alastria Alastria National Blockchain Ecosystem Alastria DID Method
did:amo: PROVISIONAL AMO blockchain mainnet AMO Labs AMO DID Method
did:bba: PROVISIONAL Ardor Attila Aldemir BBA DID Method
did:bid: PROVISIONAL bif teleinfo caict BIF DID Method
did:bnb: PROVISIONAL Binance Smart Chain Ontology Foundation Binance DID Method
did:bryk: PROVISIONAL bryk Marcos Allende, Sandra Murcia, Flavia Munhoso, Ruben Cessa bryk DID Method
did:btcr: PROVISIONAL Bitcoin Christopher Allen, Ryan Grant, Kim Hamilton Duffy BTCR DID Method
did:ccp: PROVISIONAL Quorum Baidu, Inc. Cloud DID Method
did:celo: PROVISIONAL Celo Ontology Foundation Celo DID Method
did:com: PROVISIONAL commercio.network Commercio Consortium Commercio.network DID Method
did:corda: PROVISIONAL Corda Nitesh Solanki,Moritz Platt,Pranav Kirtani Corda DID method
did:did: PROVISIONAL Decentralized Identifiers Spruce Systems, Inc. DID Identity DID Method
did:dns: PROVISIONAL Domain Name System (DNS) markus@danubetech.com, Danube Tech DNS DID Method
did:dock: PROVISIONAL Dock Dock.io Dock DID Method
did:dom: PROVISIONAL Ethereum Dominode
did:dual: PROVISIONAL Ethereum Smart ID Card Alliance Dual DID Method
did:echo: PROVISIONAL Echo Echo Technological Solutions LLC Echo DID Method
did:elastos: PROVISIONAL Elastos ID Sidechain Elastos Foundation Elastos DID Method
did:elem: PROVISIONAL Element DID Transmute ELEM DID Method
did:emtrust: PROVISIONAL Hyperledger Fabric Halialabs Pte Ltd. Emtrust DID Method
did:ens: PROVISIONAL Ethereum Oliver Terbu, ConsenSys MESH ENS DID Method
did:eosio: PROVISIONAL EOSIO Gimly Blockchain EOSIO DID Method
did:erc725: PROVISIONAL Ethereum Markus Sabadello, Fabian Vogelsteller, Peter Kolarov erc725 DID Method
did:etho: PROVISIONAL Ethereum Ontology Foundation ETHO DID Method
did:ethr: PROVISIONAL Ethereum uPort ETHR DID Method
did:evan: PROVISIONAL evan.network evan GmbH evan.network DID Method
did:example: PROVISIONAL DID Specification W3C Credentials Community Group DID Specification
did:factom: PROVISIONAL Factom Sphereon, Factomatic, Factom Inc Factom DID Method
did:future: PROVISIONAL Netease Chain Netease Blockchain Team Future DID Method
did:gatc: PROVISIONAL Ethereum, Hyperledger Fabric, Hyperledger Besu, Alastria Gataca Gataca DID Method
did:git: WITHDRAWN DID Specification Internet Identity Workshop Git DID Method
did:grg: PROVISIONAL GrgChain GRGBanking Blockchain Express Co. Ltd. GrgChain DID Method
did:hedera: PROVISIONAL Hedera Hashgraph Hedera Hashgraph, Swisscom Blockchain AG Hedera Hashgraph DID Method
did:holo: PROVISIONAL Holochain Holo.Host Holochain DID Method
did:hpass: PROVISIONAL Hyperledger Fabric IBM hpass DID Method
did:icon: PROVISIONAL ICON ICONLOOP ICON DID Method
did:infra: PROVISIONAL InfraBlockchain Blockchain Labs Infra DID Method
did:io: PROVISIONAL IoTeX IoTeX Foundation IoTeX DID Method
did:ion: PROVISIONAL Bitcoin Various DIF contributors ION DID Method
did:iota: PROVISIONAL IOTA IOTA Foundation IOTA DID Method
did:ipid: PROVISIONAL IPFS TranSendX IPID DID method
did:is: PROVISIONAL Blockcore Blockcore Blockcore DID Method
did:iwt: PROVISIONAL InfoWallet Raonsecure InfoWallet DID Method
did:jlinc: PROVISIONAL JLINC Protocol Victor Grey JLINC Protocol DID Method
did:jnctn: PROVISIONAL Jnctn Network Jnctn Limited JNCTN DID Method
did:jolo: PROVISIONAL Ethereum Jolocom Jolocom DID Method
did:keri: PROVISIONAL Ledger agnostic Dr. Sam Smith, Charles Cunningham, Phil Feairheller KERI DID Method
did:key: PROVISIONAL Ledger independent DID method based on public/private key pairs Rick Astley (thank you for your inspiration), Manu Sporny, Dmitri Zagidulin, Dave Longley, Orie Steele DID key method
did:kilt: PROVISIONAL KILT Blockchain BOTLabs GmbH KILT DID Method
did:klay: PROVISIONAL Klaytn Ontology Foundation Klaytn DID Method
did:kr: PROVISIONAL Korea Mobile Identity System Ministry of the Interior and Safety, korea Korea Mobile Identity System DID Method
did:lac: PROVISIONAL LACChain Network LACChain Alliance LAC DID Method
did:life: PROVISIONAL RChain lifeID Foundation lifeID DID Method
did:lit: PROVISIONAL LEDGIS IBCT LIT DID Method
did:meme: PROVISIONAL Ledger agnostic DID Meme Maintainers Meme DID Method
did:meta: PROVISIONAL Metadium Metadium Foundation Metadium DID Method
did:moac: PROVISIONAL MOAC MOAC Blockchain Tech, Inc. MOAC DID Method
did:monid: PROVISIONAL Ethereum Min Ju MONiD DID Method
did:morpheus: PROVISIONAL Hydra Internet of People Morpheus DID Method
did:mydata: PROVISIONAL iGrant.io iGrant.io Data Agreement DID Method
did:near: PROVISIONAL NEAR Ontology Foundation NEAR DID Method
did:nft: PROVISIONAL Ceramic Network Joel Thorstensson NFT DID Method
did:ockam: PROVISIONAL Ockam Ockam Ockam DID Method
did:omn: PROVISIONAL OmniOne OmniOne OmniOne DID Method
did:onion: PROVISIONAL Ledger agnostic Blockchain Commons Onion DID Method
did:ont: PROVISIONAL Ontology Ontology Foundation Ontology DID Method
did:op: PROVISIONAL Ocean Protocol Ocean Protocol Ocean Protocol DID Method
did:orb: PROVISIONAL Ledger agnostic SecureKey Orb DID Method
did:panacea: PROVISIONAL Panacea MediBloc Panacea DID Method
did:peer: PROVISIONAL peer Daniel Hardman peer DID Method
did:pistis: PROVISIONAL Ethereum Andrea Taglia, Matteo Sinico Pistis DID Method
did:pkh: PROVISIONAL Ledger-independent generative DID method based on CAIP-10 keypair expressions Wayne Chang, Charles Lehner, Juan Caballero did:pkh method
did:pml: PROVISIONAL PML Chain Purple Mountain Laboratories PML DID Method
did:polygon: PROVISIONAL Polygon (Previously MATIC) AyanWorks, MATIC Polygon DID Method
did:ptn: PROVISIONAL PalletOne PalletOne PalletOne DID Method
did:safe: PROVISIONAL Gnosis Safe Gnosis Ltd. SAFE DID Method
did:san: PROVISIONAL SAN Cloudchain YLZ Inc. SAN DID Method
did:schema: PROVISIONAL Multiple storage networks, currently public IPFS and evan.network IPFS 51nodes GmbH Schema Registry DID Method
did:selfkey: PROVISIONAL Ethereum SelfKey SelfKey DID Method
did:sideos: PROVISIONAL Ledger agnostic sideos GmbH sideos DID Method
did:signor: PROVISIONAL Ethereum, Hedera Hashgraph, Quorum, Hyperledger Besu Cryptonics Signor DID Method
did:sirius: PROVISIONAL ProximaX Sirius Chain ProximaX Singapore Pte. Ltd. ProximaX SiriusID DID Method
did:sol: PROVISIONAL Solana Daniel Kelleher SOL DID Method
did:sov: PROVISIONAL Sovrin Mike Lodder Sovrin DID Method
did:ssb: PROVISIONAL Secure Scuttlebutt Charles E. Lehner SSB DID Method
did:ssw: PROVISIONAL Initial Network SK telecom SSW DID Method
did:stack: PROVISIONAL Bitcoin Jude Nelson Blockstack DID Method
did:tangle: PROVISIONAL IOTA Tangle BiiLabs Co., Ltd. TangleID DID Method
did:tls: PROVISIONAL Ethereum Ulrich Gallersdörfer, Kilian Käslin TLS DID Method
did:trust: PROVISIONAL TrustChain TrustCerts GmbH Trust DID Method
did:trustbloc: PROVISIONAL Hyperledger Fabric SecureKey TrustBloc DID Method
did:trx: PROVISIONAL TRON Ontology Foundation TRON DID Method
did:ttm: PROVISIONAL TMChain Token.TM TM DID Method
did:twit: PROVISIONAL Twit DID Twit GitHub Twit DID Method
did:tyron: PROVISIONAL Zilliqa Julio Cabrapan Duarte tyronZIL DID-Method
did:tys: PROVISIONAL DID Specification Chainyard TYS DID Method
did:tz: PROVISIONAL Tezos Spruce Systems, Inc. Tezos DID Method
did:unik: PROVISIONAL uns.network Space Elephant SAS UNIK DID Method
did:unisot: PROVISIONAL Bitcoin SV UNISOT AS UNISOT DID Method
did:uns: PROVISIONAL uns.network Space Elephant SAS UNS DID Method
did:uport: DEPRECATED Ethereum uPort
did:v1: PROVISIONAL Veres One Digital Bazaar Veres One DID Method
did:vaa: PROVISIONAL bif China Academy of Information and Communications Technology (CAICT) VAA Method
did:vaultie: PROVISIONAL Ethereum Vaultie Inc. Vaultie DID Method
did:vid: PROVISIONAL VP VP Inc. VP DID Method
did:vivid: PROVISIONAL NEO2, NEO3, Zilliqa Vivid Vivid DID Method
did:vvo: PROVISIONAL Vivvo Vivvo Application Studios Vivvo DID Method
did:web: PROVISIONAL Web Oliver Terbu, Mike Xu, Dmitri Zagidulin, Amy Guy Web DID Method
did:wlk: PROVISIONAL Weelink Network Weelink Weelink DID Method
did:work: PROVISIONAL Hyperledger Fabric Workday, Inc. Workday DID Method

A. References

A.1 Normative references

[DID-CORE]
Decentralized Identifiers (DIDs) v1.0. Manu Sporny; Amy Guy; Markus Sabadello; Drummond Reed. W3C. 3 August 2021. W3C Proposed Recommendation. URL: https://www.w3.org/TR/did-core/
[RFC2119]
Key words for use in RFCs to Indicate Requirement Levels. S. Bradner. IETF. March 1997. Best Current Practice. URL: https://www.rfc-editor.org/rfc/rfc2119
[RFC8174]
Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words. B. Leiba. IETF. May 2017. Best Current Practice. URL: https://www.rfc-editor.org/rfc/rfc8174