OpenID Connect Client-Initiated Backchannel Authentication (CIBA)#

BankID with biometrics supports CIBA⁠ (opens in a new tab) for certain use cases. Get in touch to discuss your use case and enable CIBA for your client.

Steps

1. Register a client with BankID OIDC#

If you don't have a client registered with BankID OIDC⁠ (opens in a new tab) yet, you'll need to register one. Follow the instructions here⁠ (opens in a new tab) to register your application and obtain the necessary client credentials⁠ (opens in a new tab) (client_id and client_secret). You will need two clients, one for the test environment and one for the production environment.

Ensure that your client has the permissions/client and permissions/ciba scopes available.

For testing the CIBA flow in the test environment, you will need to register a test user and get access to the BankID preprod app. Detailed instructions on how to do this can be found in the testing document.

2. Get the BankID OpenID Connect Configuration#

To ensure seamless integration with BankID OIDC and avoid hardcoding specific endpoints in you application, follow these steps to dynamically fetch the OpenID Connect configuration⁠ (opens in a new tab):

1. 1

   Determine the appropriate configuration URL based on the environment:

   Environment	Url
   Production	https://auth.bankid.no/auth/realms/prod/.well-known/openid-configuration⁠ (opens in a new tab)
   Current (public test environment)	https://auth.current.bankid.no/auth/realms/current/.well-known/openid-configuration⁠ (opens in a new tab)

2. 2

   Send an HTTP GET request to the respective configuration URL using your preferred programming language or API tool.

3. 3

   Capture the response which will contain a JSON document with the configuration. By dynamically fetching the OIDC configuration, your application remains flexible, allowing for future changes or updates to the endpoints without requiring modifications to your code.

4. 4

   To enhance the reliability and performance of your integration, we strongly advise implementing response caching for the OIDC configuration.

{
  ...
  "token_endpoint": "https://auth.current.bankid.no/auth/realms/current/protocol/openid-connect/token",
  ...
}

This is a sample response. The actual response may differ.

3. Get an access token from BankID OIDC#

To obtain an access token from OIDC, follow these steps:

1. 1

   Retrieve the token endpoint URL token_endpoint dynamically from the OIDC configuration.

2. 2

   Call the token endpoint URL with your client credentials.

   You can find more detailed information about acquiring access tokens in the BankID OIDC documentation⁠ (opens in a new tab).

3. 3

   In the scope field, include the following: permissions/client, and permissions/ciba. This field specifies the scope of access granted to the token.

4. 4

   To enhance the reliability and performance of your integration, we strongly advise implementing response caching for the access token. For example based on the expires_in property in the token response.

Here's an example of a valid request in the current environment:

POST /auth/realms/current/protocol/openid-connect/token HTTP/1.1
Host: auth.current.bankid.no
Content-Type: application/x-www-form-urlencoded
Authorization: Basic <Base64-encoded client id:client secret>

grant_type=client_credentials&scope=permissions%2Fclient%20permissions%2Fciba

Make sure to replace the <Base64-encoded client id:client secret> placeholder in the Authorization header with your actual client credentials.

4. Get the BankID with biometrics OIDC configuration#

To ensure seamless integration and avoid hardcoding specific endpoints in you application, follow these steps to dynamically fetch the OpenID Connect configuration⁠ (opens in a new tab):

1. 1

   Determine the appropriate configuration URL based on the environment:

   Environment	Url
   Production	https://app.bankid.no/.well-known/openid-configuration⁠ (opens in a new tab)
   Current (public test environment)	https://current.aletheia-test.idtech.no/.well-known/openid-configuration⁠ (opens in a new tab)

2. 2

   Send an HTTP GET request to the respective configuration URL using your preferred programming language or API tool.

3. 3

   Capture the response which will contain a JSON document with the configuration. By dynamically fetching the OIDC configuration, your application remains flexible, allowing for future changes or updates to the endpoints without requiring modifications to your code.

4. 4

   To enhance the reliability and performance of your integration, we strongly advise implementing response caching for the OIDC configuration.

5. Check if user is able to authenticate with CIBA#

To be able to authenticate with CIBA, the user must be registered with a sufficiently up-to-date BankID App to support app-required flows. To check whether the user meets these requirements, make a request to the user-exists API.

6. Register the permission upfront#

To register a permission, follow these steps:

1. 1

   Construct a permission statement. See the permissions API for detailed information of how to construct the different permissions. Encode the permission statement using URL safe Base64 encoding. Below is an example of a permission statement for a payment:

   const permissionStatement = {
       "nonce": "dW5pcXVlIHZhbHVl", // Must be unique
       "id": "YmFza2V0IGlk", // Your reference
       "payments": [
           {
               "paymentId": "cGF5bWVudCBpZA", // Your reference
               "amount": "123.45",
               "currency": "NOK",
               "creditorName": "Scrooge McDuck"
           }
       ]
   }
   
   // Example implementation of a b64 URL Safe Encoder
   function b64URLSafeEncode(stringData) {
       return btoa(stringData)
           .replace(/\+/g, "-")
           .replace(/\//g, "_")
           .replace(/=/g, "");
   }
   
   b64URLSafeEncode(
       JSON.stringify(
           permissionStatement
       )
   );
   // -> "eyJub25jZSI6ImRXNXBjWFZsSUhaaGJIVmwiLCJpZCI6IlltRnphMlYwSUdsayIsInBheW1lbnRzIjpbeyJwYXltZW50SWQiOiJjR0Y1YldWdWRDQnBaQSIsImFtb3VudCI6IjEyMy40NSIsImN1cnJlbmN5IjoiTk9LIiwiY3JlZGl0b3JOYW1lIjoiU2Nyb29nZSBNY0R1Y2sifV19"
2. 2

   Send a POST request to the permissions endpoint, providing the access token received in the first step as a bearer token. Include the permission, which is the URL safe Base64 encoding of the permission statement object.

   POST /permissions/v1/ HTTP/1.1
   Host: api.current.aletheia-test.idtech.no
   Content-Type: application/json
   Authorization: Bearer <access token from step 1>
   
   {
     "type": "payment.v1",
     "iat": 1617091752,
     "exp": 1617092652,
     "permission": < URL safe b64 encoded permission statement from step 2a >,
     "intents": [
       "ciba"
     ],
     "loginHint": [
       {
         "scheme": "nnin",
         "value": "<nnin_as_string>"
       }
     ]
   }
3. 3

   On a successful request, you will receive a response body containing a permission ID, a permission token and a binding message:

   {
     "id": "1.BY.MEKrA-00GVtmvWOCDYQko_fSg93LO5n2rBnlj-X4MQg.BiDEl_CgfakqahcXjLrFet_GGpEkR_W8D-RK4hORBO0",
     "permissionToken": "eyJhbGciOiJIUzI1NiIsImtpZCI6IjB5Z3hDX3UzQlpPWXlKZ0Y3eDJ0eWtQaTRCTml2cG9KMDBmYjFzTGliUVUiLCJ0eXAiOiJKV1QifQ.eyJleHAiOjE2MTcwOTU3NDQsImlhdCI6MTYxNzA5MjE0NCwicyI6IjA6LTEjOTIzIiwicCI6IkJpREVsX0NnZmFrcWFoY1hqTHJGZXRfR0dwRWtSX1c4RC1SSzRoT1JCTzAiLCJuYmYiOjE2MTcwOTIxNDh9.39GWvNjNMSKKhKOF4t4HcDnZGNJmLmPT3f612z1VKko",
     "bindingMessage":"Farlig frakk"
   }

7. Initiate backchannel request#

Make a POST request to the bc-authorize endpoint, including the the permissionToken from step 3 as the login_hint_token to the bc-authorize endpoint.

Expand the below list below on which scopes to include (space-separated).

Passing access token as Bearer token:

POST /oidc/v1/bc-authorize HTTP/1.1
Host: oidc.current.aletheia-test.idtech.no
Content-Type: application/x-www-form-urlencoded
Authorization: Bearer <access token from client credentials exchange>

login_hint_token=<permission token from step 3>
&binding_message=<binding message from step 3>
&scope=openid%20sub_bankid

Passing access token as client_assertion form value:

POST /oidc/v1/bc-authorize HTTP/1.1
Host: oidc.current.aletheia-test.idtech.no
Content-Type: application/x-www-form-urlencoded

client_assertion=<access token from client credentials exchange>
&client_assertion_type=urn%3Aietf%3Aparams%3Aoauth%3Aclient-assertion-type%3Ajwt-bearer
&login_hint_token=<permission token from step 3>
&binding_message=<binding message from step 3>
&scope=openid%20sub_bankid

Note: Replace string with the actual login_hint_token and provide appropriate values for other fields.

After calling the bc-authorize endpoint, you will receive the following response:

{
  "auth_req_id": "stringstring",
  "expires_in": 0,
  "interval": 0
}

The bc-authorize endpoint returns auth_req_id which you will use when posting a request to the token endpoint afterwards.

8. Poll for the result#

1. 1

   Make a POST request to the token endpoint using the CibaTokenRequest schema. You may call call this endpoint every interval seconds, as specified in the response from the previous step.

   Passing access token as Bearer token:

   POST /oidc/v1/token HTTP/1.1
   Host: oidc.current.aletheia-test.idtech.no
   Content-Type: application/x-www-form-urlencoded
   Authorization: Bearer <access token from client credentials exchange>
   
   grant_type=urn%3Aopenid%3Aparams%3Agrant-type%3Aciba
   &auth_req_id=<auth_req_id from step 7>
   

   Passing access token as client_assertion form value:

   POST /oidc/v1/token HTTP/1.1
   Host: oidc.current.aletheia-test.idtech.no
   Content-Type: application/x-www-form-urlencoded
   
   client_assertion=<access token from client credentials exchange>
   &client_assertion_type=urn%3Aietf%3Aparams%3Aoauth%3Aclient-assertion-type%3Ajwt-bearer
   &grant_type=urn%3Aopenid%3Aparams%3Agrant-type%3Aciba
   &auth_req_id=<auth_req_id from step 7>
   

   Note: Replace string with the actual values, including the auth_req_id.

2. 2

   While the user haven't completed the authentication yet the token endpoint will respond with a 400 authorization_pending error.

   {
     "error": "authorization_pending",
     "error_description": "User has not yet granted authorization"
   }
3. 3

   Keep polling this endpoint until you get a different error with a 400 response, or a 200 response with the id_token in the response body.

   Here's an example of a successful response:

   {
     "token_type": "string",
     "expires_in": 0,
     "id_token": "string"
   }

   And here's an example of an errored response:

   {
     "error": "access_denied",
     "error_description": "Authorization was denied by the user"
   }

9. Validate the ID token#

To ensure the authenticity and integrity of the received ID token, you must perform the following verification:

• Verify that the algorithm used to sign the ID token is found in the BankID with biometrics OIDC configuration under id_token_signing_alg_values_supported.
• Verify that the token is signed by a key from our JWKS (JSON Web Key Set)⁠ (opens in a new tab) Document. The URI for the JWKS document can be found under the jwks_uri key in the BankID with biometrics OIDC configuration document you retrieved in step 4. We recommend caching the JWKS for 30 minutes, and also fetching a new JWKS if the kid in the ID token does not match any key in the cached JWKS.

We recommend verifying these additional properties:

• iss (issuer) - The issuer of the token must match the issuer in the BankID with biometrics OIDC configuration.
• aud (audience) - The audience of the token must match your client ID.
• exp (expiration time) - The token must not be expired.
• iat (issued at) - The token must not be issued in the future.
• acr (authentication context class reference) is only relevant if you've asked for forced step up. If relevant must be verified to be the expected value.

Further information on how to validate the ID token can be found in the OpenID Connect Core specification⁠ (opens in a new tab).

10. Get the signed permission (optional)#

To get the signed permission you can send in a GET request to the permissionId/grant endpoint. The permissionId you use is the one that you got from your permissions POST request. Be aware that it can return a 404 error code (permission not yet granted) but as mentioned in the api specification you can set up a polling request on the permissionId/grant endpoint until your initial permission has been signed.

If your permission has been successfully granted you will receive this response:

{
  "gv": 1,
  "pt": "string",
  "type": "string",
  "rpId": "bankid-app",
  "sv": "2020-10-30@deadbeef",
  "iat": 1800000000,
  "iss": "string",
  "nonce": "string",
  "proofKeyId": "string",
  "sub": "nnin:010112345",
  "permissionId": "string",
  "digest": "string"
}

The grant is a JWT that can be validated as follows:

• In the BankID with biometrics OIDC configuration (as mentioned here) get the Grant JWK set from the URI pointed to by the jwks_uri_grants property in this document.
• Check that the JWT is signed by one of the keys in the Grant JWK set. You can find a suitable library for performing this verification at https://jwt.io/libraries⁠ (opens in a new tab).
• Check that the nonce claim inside the token payload is equal to the nonce in the permission statement created in step 2.