Update DID Documents

You can extend DID Documents by adding verification methods, services and custom properties. A verification method adds public keys, which can be used to digitally sign things like a DID message or a verifiable credential, while a service can provide metadata around the identity via URIs.

Verification Methods

As demonstrated by the example below, the IOTA Identity framework offers easy-to-use methods for adding verification methods.

Properties

You can specify the following properties for a verification method:

• id: A DID URL for the verification method. You can specify it by setting the fragment.
• type: Specifies the type of the verification method. The framework supports Ed25519 and X25519 key types. This property is automatically filled by the framework when specifying the verification material.
• publicKeyMultibase: A multi-base encoded public key which concludes the verification material. This can be automatically generated by the framework or manually provided by users.

Verification Relationships

Verification relationships express the relationship between the DID subject and the verification method. You can use it to specify the purpose of the verification method.

Relationships

The Identity Framework supports the following relationships:

• Authentication: Used to specify authentication methods for the DID subject.
• Assertion: Used to verify verifiable credentials.
• Key Agreement: Used for establishing secure communication channels.
• Capability Invocation: Can be used to authorize updates to the DID Document.
• Capability Delegation: A mechanism to delegate cryptographic capability to another party.

Verification methods can be either embedded or referenced. Referencing verification methods allows them to be used by more than one verification relationship. When you create a verification method using the Identity Framework, specifying the MethodScope option will result in an embedded verification method. Leaving that option unset will create the verification method as a map entry of the verificationMethod property. You can also add verification relationships afterward using references.

note

Updates to the DID Document are done through the invocation of Identity::execute_update API by an Identity's controller. The public key or address of the controller does not need to be a verification method in the DID Document, since the controller is authenticated through possession of a ControllerCap token.

Services

Services allow you to add other ways of communicating with the DID subject. An endpoint included in the DID Document can offer a way of reaching services for different purposes like authentication, communicating, and discovery.

Properties

You can specify the following properties for a service:

• id: A DID URL for referencing the service in the DID document. You can specify it by setting the fragment.
• type: A string used to maximize interoperability between services. The framework does not perform any checks on the content of this string.
• serviceEndpoint: A URL that points to the service endpoint.

Create Identity

Before you can update anything, you will need to create an Identity.

Rust

    // Create a new client to interact with the IOTA ledger.
    // create new client to interact with chain and get funded account with keys
    let storage = get_memstorage()?;
    let identity_client = get_client_and_create_account(&storage).await?;
    // create new DID document and publish it
    let (document, vm_fragment_1) = create_did_document(&identity_client, &storage).await?;
    let did: IotaDID = document.id().clone();

This creates and publishes an Identity object containing a DID Document with one verification method.

{
    "doc": {
        "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a",
        "verificationMethod": [
            {
                "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a#HZ11e0XacuODQw5FcoMHtcdxl8oXHbSnIhQMUgVzWBE",
                "controller": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a",
                "type": "JsonWebKey",
                "publicKeyJwk": {
                    "kty": "OKP",
                    "alg": "EdDSA",
                    "kid": "HZ11e0XacuODQw5FcoMHtcdxl8oXHbSnIhQMUgVzWBE",
                    "crv": "Ed25519",
                    "x": "475CGLtezvySFMCHhx6hE9S97MIYMLb4B-pbVEHaCtY"
                }
            }
        ]
    },
    "meta": {
        "created": "2023-11-16T20:40:03Z",
        "updated": "2023-11-16T20:40:03Z",
    }
}

Add a Verification Method

Rust

  // Insert a new Ed25519 verification method in the DID document.
  let fragment_2: String = document
    .generate_method(
      &storage,
      JwkMemStore::ED25519_KEY_TYPE,
      JwsAlgorithm::EdDSA,
      None,
      MethodScope::VerificationMethod,
    )
    .await?;

This creates a new verification method that includes a newly generated Ed25519 public key.

{
    "doc": {
        "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a",
        "verificationMethod": [
            {
                "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a#HZ11e0XacuODQw5FcoMHtcdxl8oXHbSnIhQMUgVzWBE",
                "controller": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a",
                "type": "JsonWebKey",
                "publicKeyJwk": {
                    "kty": "OKP",
                    "alg": "EdDSA",
                    "kid": "HZ11e0XacuODQw5FcoMHtcdxl8oXHbSnIhQMUgVzWBE",
                    "crv": "Ed25519",
                    "x": "475CGLtezvySFMCHhx6hE9S97MIYMLb4B-pbVEHaCtY"
                }
            },
            {
                "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a#yJz-sPlCmd432JKqK_hkiPml2kj22Jv0aAFy_2jJ8nE",
                "controller": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a",
                "type": "JsonWebKey",
                "publicKeyJwk": {
                    "kty": "OKP",
                    "alg": "EdDSA",
                    "kid": "yJz-sPlCmd432JKqK_hkiPml2kj22Jv0aAFy_2jJ8nE",
                    "crv": "Ed25519",
                    "x": "h8ndZ4_Urmzf4xN4emqS8r5q4pAQvAh0k2YHq5JLBBo"
                }
            }
        ]
    },
    "meta": {
        "created": "2023-11-16T20:40:03Z",
        "updated": "2023-11-16T20:40:03Z",
    }
}

Add Verification Relationships

You can attach verification relationships to a verification method by referencing its fragment.

Rust

// Attach a new method relationship to the inserted method.
document.attach_method_relationship(
  &document.id().to_url().join(format!("#{fragment_2}"))?,
  MethodRelationship::Authentication,
)?;

This will add Authentication relationship to the verification method with the fragment key-1. Note that Authentication references the already included key-2 verification method:

{
    "doc": {
        "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a",
        "verificationMethod": [
            {
                "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a#HZ11e0XacuODQw5FcoMHtcdxl8oXHbSnIhQMUgVzWBE",
                "controller": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a",
                "type": "JsonWebKey",
                "publicKeyJwk": {
                    "kty": "OKP",
                    "alg": "EdDSA",
                    "kid": "HZ11e0XacuODQw5FcoMHtcdxl8oXHbSnIhQMUgVzWBE",
                    "crv": "Ed25519",
                    "x": "475CGLtezvySFMCHhx6hE9S97MIYMLb4B-pbVEHaCtY"
                }
            },
            {
                "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a#yJz-sPlCmd432JKqK_hkiPml2kj22Jv0aAFy_2jJ8nE",
                "controller": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a",
                "type": "JsonWebKey",
                "publicKeyJwk": {
                    "kty": "OKP",
                    "alg": "EdDSA",
                    "kid": "yJz-sPlCmd432JKqK_hkiPml2kj22Jv0aAFy_2jJ8nE",
                    "crv": "Ed25519",
                    "x": "h8ndZ4_Urmzf4xN4emqS8r5q4pAQvAh0k2YHq5JLBBo"
                }
            }
        ],
        "authentication": [
            "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a#yJz-sPlCmd432JKqK_hkiPml2kj22Jv0aAFy_2jJ8nE"
        ]
    },
    "meta": {
        "created": "2023-11-16T20:40:03Z",
        "updated": "2023-11-16T20:40:03Z",
    }
}

Add a Service

You can also add custom properties can to a service by setting properties:

Rust

  // Add a new Service.
  let service: Service = Service::from_json_value(json!({
    "id": document.id().to_url().join("#linked-domain")?,
    "type": "LinkedDomains",
    "serviceEndpoint": "https://iota.org/"
  }))?;
  assert!(document.insert_service(service).is_ok());
  document.metadata.updated = Some(Timestamp::now_utc());

The updated Document with the newly created service looks as follows.

{
    "doc": {
        "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a",
        "verificationMethod": [
            {
                "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a#HZ11e0XacuODQw5FcoMHtcdxl8oXHbSnIhQMUgVzWBE",
                "controller": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a",
                "type": "JsonWebKey",
                "publicKeyJwk": {
                    "kty": "OKP",
                    "alg": "EdDSA",
                    "kid": "HZ11e0XacuODQw5FcoMHtcdxl8oXHbSnIhQMUgVzWBE",
                    "crv": "Ed25519",
                    "x": "475CGLtezvySFMCHhx6hE9S97MIYMLb4B-pbVEHaCtY"
                }
            },
            {
                "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a#yJz-sPlCmd432JKqK_hkiPml2kj22Jv0aAFy_2jJ8nE",
                "controller": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a",
                "type": "JsonWebKey",
                "publicKeyJwk": {
                    "kty": "OKP",
                    "alg": "EdDSA",
                    "kid": "yJz-sPlCmd432JKqK_hkiPml2kj22Jv0aAFy_2jJ8nE",
                    "crv": "Ed25519",
                    "x": "h8ndZ4_Urmzf4xN4emqS8r5q4pAQvAh0k2YHq5JLBBo"
                }
            }
        ],
        "authentication": [
            "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a#yJz-sPlCmd432JKqK_hkiPml2kj22Jv0aAFy_2jJ8nE"
        ],
        "service": [
            {
                "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a#linked-domain",
                "type": "LinkedDomains",
                "serviceEndpoint": "https://iota.org/"
            }
        ]
    },
    "meta": {
        "created": "2023-11-16T20:40:03Z",
        "updated": "2023-11-16T20:40:08Z",
    }
}

Remove a Verification Method

You can also remove verification methods at any time using the following snippet:

Rust

// Remove a verification method.
let original_method: DIDUrl = document.resolve_method(fragment_1.as_str(), None).unwrap().id().clone();
document.purge_method(&storage, &original_method).await.unwrap();

This removes the original verification method with the fragment key-1.

{
    "doc": {
        "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a",
        "verificationMethod": [
            {
                "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a#yJz-sPlCmd432JKqK_hkiPml2kj22Jv0aAFy_2jJ8nE",
                "controller": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a",
                "type": "JsonWebKey",
                "publicKeyJwk": {
                    "kty": "OKP",
                    "alg": "EdDSA",
                    "kid": "yJz-sPlCmd432JKqK_hkiPml2kj22Jv0aAFy_2jJ8nE",
                    "crv": "Ed25519",
                    "x": "h8ndZ4_Urmzf4xN4emqS8r5q4pAQvAh0k2YHq5JLBBo"
                }
            }
        ],
        "authentication": [
            "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a#yJz-sPlCmd432JKqK_hkiPml2kj22Jv0aAFy_2jJ8nE"
        ],
        "service": [
            {
                "id": "did:iota:tst:0x19ed80fbd2a644fc2347e27e46e09d42b89df9b1ba09ae41832a9d47d686776a#linked-domain",
                "type": "LinkedDomains",
                "serviceEndpoint": "https://iota.org/"
            }
        ]
    },
    "meta": {
        "created": "2023-11-16T20:40:03Z",
        "updated": "2023-11-16T20:40:08Z",
    }
}

Full Example Code

Rust

examples/0_basic/1_update_did.rs

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See full example on GitHub