Client Registration

Dynamic Client Registration (DCR)

Dynamic client registration refers to the process by which a client submits a registration request to the Authorization server and how that request is served by the Authorization server. It is explained in the following specifications:

• For OpenID Connect relying parties
• For OAuth 2.0 client (without OpenID Connect features)
• Client management (CRUD) operations
• OpenBanking OpenID Dynamic Client Registration

Client Registration endpoint

The URI to dynamically register a client to a Janssen Auth Server can be found by checking the registration_endpoint claim of the OpenID Connect configuration reponse, typically deployed at

https://<my.jans.server>/.well-known/openid-configuration

Configuring Janssen AS to allow clients to dynamically register

The Janssen Authorization server will serve a DCR request if the following configuration parameters are set:

1. dynamicRegistrationEnabled : true or false
2. dynamicRegistrationExpirationTime : Expiration time in seconds for clients created with dynamic registration, 0 or -1 means never expire

Configure the Janssen AS using steps explained in the link

Client registration Requests

Client registration request primarily does two things: Communicate client metadata to the authorization server, and optionally authenticate.

There are different ways in which the client metadata is communicated to the authorization server using dynamic client registration requests.

• Using request body
• Using signed request object (JWT)
• Using software statement

Using request body

A minimal DCR request with only mandatory parameters, looks like the one below.

curl -X POST -k -H 'Content-Type: application/json' -i 'https://my.jans.server/jans-auth/restv1/register' \
             --data '{"redirect_uris": ["https://my.jans.client/page"]}'

If the registration is successful, Janssen Server will respond with http response code 201 with JSON body as shown in example below:

{
    "allow_spontaneous_scopes": false,
    "application_type": "web",
    "rpt_as_jwt": false,
    "registration_client_uri": "https://my.jans.server/jans-auth/restv1/register?client_id=85192707-a38c-496c-806c-ef01a6a3ae4a",
    "tls_client_auth_subject_dn": "",
    "run_introspection_script_before_jwt_creation": false,
    "registration_access_token": "eaee20de-54ce-4217-b960-6b72b55e6cab",
    "client_id": "85192707-a38c-496c-806c-ef01a6a3ae4a",
    "token_endpoint_auth_method": "client_secret_basic",
    "scope": "profile work_phone phone user_name device_sso openid permission uma_protection address email clientinfo org_name offline_access https://jans.io/auth/ssa.portal test https://jans.io/auth/ssa.admin https://jans.io/auth/ssa.developer",
    "client_secret": "4148f812-92d6-4245-80e0-243524b3b6a4",
    "client_id_issued_at": 1678700818,
    "backchannel_logout_uri": [],
    "backchannel_logout_session_required": false,
    "client_name": "my.jans.client",
    "par_lifetime": 600,
    "spontaneous_scopes": [],
    "id_token_signed_response_alg": "RS256",
    "access_token_as_jwt": false,
    "grant_types": [
        "authorization_code",
        "refresh_token"
    ],
    "subject_type": "pairwise",
    "keep_client_authorization_after_expiration": false,
    "require_par": false,
    "redirect_uris": ["https://my.jans.client/page"],
    "redirect_uris_regex": "",
    "additional_audience": [],
    "frontchannel_logout_session_required": false,
    "client_secret_expires_at": 1678787218,
    "access_token_signing_alg": "RS256",
    "response_types": ["code"]
}

In a typical DCR request the client or developer calls the client registration endpoint with a set of client metadata as specified in RFC7591

curl -X POST -k -i 'https://my.jans.server/jans-auth/restv1/register'  \
     --data '{ \
                   "redirect_uris": ["https://client.example.org/cb"] \
               "client_id": "c3BhdRkqfX", \
               "client_secret": "bd136123eeffeef234235805d", \
               "grant_types": ["authorization_code", "refresh_token"], \
               "token_endpoint_auth_method": "client_secret_basic", \
               "jwks_uri": "https://client.example.org/my_public_keys.jwks", \
               "client_name": "My Example", \
               "client_name#fr": "Mon Exemple" \
         }' 

Using signed request object (JWT)

In some use-cases like FAPI implementation, DCR request payload is a JWT.

Example:

curl -X POST -k -H 'Content-Type: application/jwt' \
    -H 'Accept: application/json' \
    -i 'https://my-jans-server/jans-auth/restv1/register'  \
    --data 'eyJraWQiOiJrWTIyZXBUT......ueOg2HkjpggwAEP84jq9Q'

When such will be the nature of client registration requests, the following configuration properties should be set in the authorization server:

• dcrSignatureValidationEnabled - enables DCR signature validation
• dcrSignatureValidationJwksUri - specifies JWKS URI for all DCR's validations.
• dcrSignatureValidationJwks - specifies JWKS for all DCR's validations.

Configure the Janssen AS using steps explained in the link

Using software statement

A signed assertion from a trusted party, a Software statement or Software Statement Assertion (SSA), is used to dynamically register clients to an Authorization server.

Example:

curl -X POST https://my.jans.server/jans-auth/restv1/register \
       -H "Content-Type: application/json" \
   --data-binary @- <<DATA \
{ "redirect_uris": [ "https://client.example.org/cab1" ], \
  "software_statement":"eyJ0eXAi........j3ouyeYOv8", \
  "jwks_uri":"https://my.portal/portal/jwks" \
} DATA

To enable client registrations using Software statements, the AS should be configured using the following configuration parameters:

• softwareStatementValidationType - The value of this variable is one of the following:
  • NONE - validation is skipped for software statement
  • SCRIPT - (default), invokes getSoftwareStatementJwks of dynamic registration script which has to return jwks.
  • JWKS - claim name within software statement that has inlined JWKS
  • JWKS_URI - claim name within software statement that points to JWKS URI that should lead to keys.
• dcrSignatureValidationSoftwareStatementJwksURIClaim - specifies claim name inside software statement that should point to JWKS URI.
• dcrSignatureValidationSoftwareStatementJwksClaim - specifies claim name inside software statement. Value of claim should point to inlined JWKS.

Configure the AS using steps explained in the link

Special mention about FAPI:

In case of a typical client registration request in FAPI implementation, the request object which is a signed JWT (as seen in point 3) is also called an SSA (Software statement Assertion) or DCR payload. This SSA can contain the software_statement inside it which is also a signed JWT. Each of the JWTs, the outer JWT called the SSA and the inner JWT called the software_statement are signed by different entities - the TPP and OBIE respectively.

Security Pointers

If dynamicRegistrationEnabled is enabled in the Authorization Server, assess the following points to minimize potential exposure of sensitive personal data:

1. trustedClientEnabled and dynamicRegistrationPersistClientAuthorizations properties determine whether clients are trusted and if consent should be sought from the user before releasing their personal data to the RP
2. dynamicRegistrationScopesParamEnabled controls whether default scopes are globally enabled. If dynamicRegistrationScopesParamEnabled is true then scopes defined as default will be automatically added to any dynamically registered client entry without consent of OP's administrator. Therefore, make an informed decision before setting this field to true.

CURL commands to configure Jans-auth server

Jans-auth server is configured using Jans Config Api :

Obtain the access token

curl -u "put_client_id_here:put_config_api_client_secret_here" https://<your.jans.server>/jans-auth/restv1/token \
     -d  "grant_type=client_credentials&scope=https://jans.io/oauth/jans-auth-server/config/properties.write"

Patch jans-auth server configurations

Patch jans-auth server configurations to reflect anExampleConfigField with the value anExampleConfigField_value

curl -X PATCH -k -H 'Content-Type: application/json-patch+json' \
 -i 'https://<your.jans.server>/jans-config-api/api/v1/jans-auth-server/config' \
 -H "Authorization: Bearer put_access_token_here" --data '[
    {
     "op": "add",
     "path": "anExampleConfigField",
     "value": "anExampleConfigField_value"
     }
    ]'

For example, to patch the jans-auth server configurations to reflect dynamicRegistrationEnabled with value as true

curl -X PATCH -k -H 'Content-Type: application/json-patch+json' \
-i 'https://<your.jans.server>/jans-config-api/api/v1/jans-auth-server/config' \
-H "Authorization: Bearer put_access_token_here" --data '[
 {
  "op": "add",
  "path": "dynamicRegistrationEnabled",
  "value": "true"
  }
 ]'

Client metadata

Command to obtain metadata schema

/opt/jans/jans-cli/config-cli.py --schema /components/schemas/Client

Output:

{
  "dn": "string",
  "inum": "string",
  "displayName": "string",
  "clientSecret": "string",
  "frontChannelLogoutUri": "string",
  "frontChannelLogoutSessionRequired": true,
  "registrationAccessToken": "string",
  "clientIdIssuedAt": "2022-08-31T10:39:31.385Z",
  "clientSecretExpiresAt": "2022-08-31T10:39:31.385Z",
  "redirectUris": [
    "https://client.example.org/cb"
  ],
  "claimRedirectUris": [
    "string"
  ],
  "responseTypes": [
    "code"
  ],
  "grantTypes": [
    "authorization_code"
  ],
  "applicationType": "web",
  "contacts": [
    "string"
  ],
  "idTokenTokenBindingCnf": "string",
  "logoUri": "string",
  "clientUri": "string",
  "policyUri": "string",
  "tosUri": "string",
  "jwksUri": "string",
  "jwks": "{ \"keys\" : [ { \"e\" : \"AQAB\", \"n\" : \"gmlDX_mgMcHX..\" ] }",
  "sectorIdentifierUri": "string",
  "subjectType": "pairwise",
  "idTokenSignedResponseAlg": "HS256",
  "idTokenEncryptedResponseAlg": "RSA1_5",
  "idTokenEncryptedResponseEnc": "A128CBC+HS256",
  "userInfoSignedResponseAlg": "HS256",
  "userInfoEncryptedResponseAlg": "RSA1_5",
  "userInfoEncryptedResponseEnc": "A128CBC+HS256",
  "requestObjectSigningAlg": "HS256",
  "requestObjectEncryptionAlg": "RSA1_5",
  "requestObjectEncryptionEnc": "A128CBC+HS256",
  "tokenEndpointAuthMethod": "client_secret_basic",
  "tokenEndpointAuthSigningAlg": "HS256",
  "defaultMaxAge": 1000000,
  "requireAuthTime": true,
  "defaultAcrValues": [
    "string"
  ],
  "initiateLoginUri": "string",
  "postLogoutRedirectUris": [
    "https://client.example.org/logout/page1",
    "https://client.example.org/logout/page2",
    "https://client.example.org/logout/page3"
  ],
  "requestUris": [
    "string"
  ],
  "scopes": [
    "read write dolphin"
  ],
  "claims": [
    "string"
  ],
  "trustedClient": false,
  "lastAccessTime": "2022-08-31T10:39:31.385Z",
  "lastLogonTime": "2022-08-31T10:39:31.385Z",
  "persistClientAuthorizations": true,
  "includeClaimsInIdToken": false,
  "refreshTokenLifetime": 100000000,
  "accessTokenLifetime": 100000000,
  "customAttributes": [
    {
      "name": "name, displayName, birthdate, email",
      "multiValued": true,
      "values": [
        "string"
      ]
    }
  ],
  "customObjectClasses": [
    "string"
  ],
  "rptAsJwt": true,
  "accessTokenAsJwt": true,
  "accessTokenSigningAlg": "HS256",
  "disabled": false,
  "authorizedOrigins": [
    "string"
  ],
  "softwareId": "4NRB1-0XZABZI9E6-5SM3R",
  "softwareVersion": "2.1",
  "softwareStatement": "string",
  "attributes": {
    "tlsClientAuthSubjectDn": "string",
    "runIntrospectionScriptBeforeAccessTokenAsJwtCreationAndIncludeClaims": true,
    "keepClientAuthorizationAfterExpiration": true,
    "allowSpontaneousScopes": true,
    "spontaneousScopes": [
      "string"
    ],
    "spontaneousScopeScriptDns": [
      "string"
    ],
    "updateTokenScriptDns": [
      "string"
    ],
    "backchannelLogoutUri": [
      "string"
    ],
    "backchannelLogoutSessionRequired": true,
    "additionalAudience": [
      "string"
    ],
    "postAuthnScripts": [
      "string"
    ],
    "consentGatheringScripts": [
      "string"
    ],
    "introspectionScripts": [
      "string"
    ],
    "rptClaimsScripts": [
      "string"
    ],
    "ropcScripts": [
      "string"
    ],
    "parLifetime": 0,
    "requirePar": true,
    "jansAuthSignedRespAlg": "string",
    "jansAuthEncRespAlg": "string",
    "jansAuthEncRespEnc": "string",
    "jansSubAttr": "string",
    "redirectUrisRegex": "string",
    "jansAuthorizedAcr": [
      "string"
    ],
    "jansDefaultPromptLogin": true
  },
  "backchannelTokenDeliveryMode": "poll",
  "backchannelClientNotificationEndpoint": "string",
  "backchannelAuthenticationRequestSigningAlg": "RS256",
  "backchannelUserCodeParameter": true,
  "expirationDate": "2022-08-31T10:39:31.385Z",
  "deletable": false,
  "jansId": "string",
  "description": "string"
}

Signed DCR and SSA validation

In OpenBanking case DCR (Dynamic Client Request) is signed and must contain SSA (Software Statement Assertion) inside it.

Non-Normative Example:

POST /register HTTP/1.1
Content-Type: application/jwt
Accept: application/json
Host: auth.bankone.com

eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJJREFtYX...

Decoded DCR Example:

{
    "typ": "JWT",
    "alg": "ES256",
    "kid": "ABCD1234"
}
{
    "iss": "Amazon TPPID",
    "iat": 1492760444,
    "exp": 1524296444,
    "aud": "https://authn.gluu.org",
    "scope": "openid makepayment",
    "token_endpoint_auth_method": "private_key_jwt",
    "grant_types": ["authorization_code", "refresh_token", "client_credentials"],
    "response_types": ["code"],
    "id_token_signed_response_alg": "ES256",
    "request_object_signing_alg": "ES256",
    "software_id": "65d1f27c-4aea-4549-9c21-60e495a7a86f",
    "software_statement":  "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJlbXB0eSIsInN1YiI6IjEyMzQ1Njc4OTAiLCJuYW1lIjoiSm9obiBEb2UiLCJhZG1pbiI6dHJ1ZSwic2NvcGUiOiJzY29wZTEgc2NvcGUyIiwiY2xhaW1zIjoiY2xhaW0xIGNsYWltMiIsImlhdCI6MTY2OTgwNjc2MywiZXhwIjoxNjY5ODEwMzYzfQ.db0WQh2lmHkNYCWT8tSW684hqWTPJDTElppy42XM_lc"
}
{
    Signature
}

AS has dcrSsaValidationConfigs configuration value which holds json array. It can be used to validated both DCR and SSA.

Single item of this array has following properties:

• id - REQUIRED primary key for the entity
• type - REQUIRED either ssa or dcr
• displayName - Human friendly name in case we build an admin GUI for this
• description - Human friendly details
• scope - For SSA only -- list of allowed scopes the issuer can enable the client to request automatically. If not present, all scopes are allowed.
• allowed_claims - Any claims not listed in this list will be dropped. If not present, all claims are allowed.
• jwks - Public key
• jwks_uri - URI of public key
• issuers - For MTLS, list of issuers trusted
• configuration_endpoint - points to discovery page, e.g. https://examle.com/.well-known/openid-configuration
• configuration_endpoint_claim - e.g. ssa_jwks_endpoint
• shared_secret - for MTLS HMAC

One of jwks, jwks_uri or issuers or configuration_endpoint is required.

Non-normative example of dcrSsaValidationConfigs

[ {
  "id" : "735ee1c0-895d-4398-9c1b-9ad852257cc0",
  "type" : "DCR",
  "scopes" : [ "read", "write" ],
  "allowedClaims" : [ "exp", "iat" ],
  "jwks" : "{jwks here}",
  "issuers" : [ "Acme" ],
  "sharedSecret" : "secret"
}, {
  "id" : "7907cd0b-0f9f-4b4f-aaa2-0d0614546246",
  "type" : "SSA",
  "scopes" : [ "my_read", "my_write" ],
  "allowedClaims" : [ "test_exp", "test_iat" ],
  "jwks" : "{jwks here}",
  "issuers" : [ "jans-auth" ],
  "sharedSecret" : "secret"
}, {
  "id" : "1e95c9b1-04d0-4440-9362-88f4e1e62d76",
  "type" : "SSA",
  "jwks" : "{jwks here}",
  "issuers" : [ "empty" ],
  "sharedSecret" : "secret"
} ]

Signed DCR validation

DCR can be validated with two approaches.

Via dcrSsaValidationConfigs configuration property - RECOMMENDED

When create entry in dcrSsaValidationConfigs configuration property : - type MUST be equal to DCR value - issuers MUST have value which equals to iss claim in DCR.

Via other configuration properties

• dcrSignatureValidationJwks - specifies JWKS for DCR's validations
• dcrSignatureValidationJwksUri - specifies JWKS URI for DCR's validations
• dcrIssuers - List of issues if MTLS private key is used to sign DCR JWT
• dcrSignatureValidationSharedSecret - if HMAC is used, this is the shared secret
• dcrSignatureValidationEnabled - boolean value enables DCR signature validation. Default is false
• dcrSignatureValidationSoftwareStatementJwksURIClaim - specifies claim name inside software statement. Value of claim should point to JWKS URI
• dcrSignatureValidationSoftwareStatementJwksClaim - specifies claim name inside software statement. Value of claim should point to inlined JWKS
• dcrAuthorizationWithClientCredentials - boolean value indicating if DCR authorization to be performed using client credentials

SSA Validation

SSA is validated based on softwareStatementValidationType which is enum.

1. softwareStatementValidationType=builtin - validation is performed against dcrSsaValidationConfigs configuration property, where
2. type MUST be equal to SSA value
3. issuers MUST have value which equals to iss claim in DCR.
4. softwareStatementValidationType=script - jwks and hmac secret are returned by dynamic client registration script
5. softwareStatementValidationType=jwks_uri, allows to specify jwks_uri claim name from software_statement. Claim name specified by softwareStatementValidationClaimName configuration property.
6. softwareStatementValidationType=jwks, allows to specify jwks claim name from software_statement. Claim name specified by softwareStatementValidationClaimName configuration property.
7. softwareStatementValidationType=none, no validation.

Customizing the behavior of the AS using Interception script

Janssen's allows developers to register a client with the Authorization Server (AS) without any intervention by the administrator. By default, all clients are given the same default scopes and attributes. Through the use of an interception script, this behavior can be modified. These scripts can be used to analyze the registration request and apply customizations to the registered client. For example, a client can be given specific scopes by analyzing the Software Statement that is sent with the registration request.

Further reading here

Dynamic registration custom attributes

CRUD Operations

Janssen Server allows client management through client configuration endpoint (RFC 7592).

JSON response to client registration request contains registration_client_uri and registration_access_token data elements. The URI mentioned using registration_client_uri provides functionality to read, update and delete the client. This endpoint is a protected endpoint where request has to be authenticated using access token registration_access_token.

Read client metadata

A read request to the same client that got created in earlier section should be as shown in the example below. HTTP method GET is used to send the request which signifies that it is a request to read client metadata.

curl -k -H 'Authorization: Bearer eaee20de-54ce-4217-b960-6b72b55e6cab' \
-i 'https://my.jans.server/jans-auth/restv1/register?client_id=85192707-a38c-496c-806c-ef01a6a3ae4a'

JSON response from Janssen Server will contain the current state of client metadata.

Update client metadata

Client metadata can be updated by sending request with PUT HTTP method to registration_client_uri. Janssen Server replaces current metadata with the one sent with update request as outlined in the specification

Delete Client

Client can be deleted by sending a request using DELETE method to registration_client_uri.

A successful delete action will invalidate the "client_id", "client_secret", and "registration_access_token" for this client, thereby preventing the "client_id" from being used at either the authorization endpoint or token endpoint of the authorization server.

Internationalization for Client metadata

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Last update: 2023-03-14
Created: 2022-07-21