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Updated to amend "organisation_competent_authority_claims" from an array to an object, so that it matches the Open Banking Directory implementation as approved by TDA on
This specification defines two mechanisms by which a Primary Technical Contact (PTC) for a Trusted Third Party (TPP) may submit a Software Statement Assertion (SSA) to an Account Servicing Payment Services Provider (ASPSP) for the purposes of receiving a client credential enabling access to UK OpenBanking APIs on behalf of ASPSP Customers. The automated mechanism profiles [RFC7591]. The manual mechanism uses web single sign-on for secure access by the PTC to a portal operated by the ASPSP that is based on the original PTC credentials used to generate the SSA.
This specification uses the terms "access token", "authorization code", "authorization endpoint", "authorization grant", "authorization server", "client", "client identifier", "client secret", "grant type", "protected resource", "redirection URI", "refresh token", "resource owner", "resource server", "response type", and "token endpoint" defined by OAuth 2.0 [RFC6749] and uses the term "Claim" defined by JSON Web Token (JWT) [RFC7519].
The payload of an OpenBanking SSA MUST be a compliant software statement according to [RFC7591]. The SSA MUST also be a compliant JWT according to [RFC7519]. The following metadata profiles the metadata in [RFC7591] and [RFC7519]:
Unique Identifier for TPP Client Software
Time SSA issued
The following software metadata is additionally defined for this profile:
The Client ID Registered at OB used to access OB resources
Human-readable detailed description of the client
Human-readable Software Name
The website or resource root uri
The version number of the software should a TPP choose to register and / or maintain it
Requested additional field to avoid certificate check
Contains all active signing and network certs for the software
Contains all revoked signing and network certs for the software
Link to the TPP logo. Note, ASPSPs are not obliged to display images hosted by third parties
ASPSP Requested additional field to indicate that this software is "Test" or "Live" the default is "Live". Impact and support for "Test" software is up to the ASPSP.
A reference to fourth party organsiation resource on the OB Directory if the registering TPP is acting on behalf of another.
The type of organisaion that this software has a relationship with. Regulated on OB Directory, Not regulated, Regulated not On OB Directory
A link to the software's policy page
Registered client callback endpoints as registered with Open Banking
A multi value list of PSD2 roles that this software is authorized to perform.
A link to the software's terms of service page
The following Organisational metadata is defined for this profile:
Authorisations granted to the organsiation by an NCA
Included to cater for voluntary withdrawal from OB scenarios
Active, Revoked or Withdrawn
The Unique TPP or ASPSP ID held by OpenBanking.
Legal Entity Identifier or other known organisation name
JSON array of objects containing a triplet of name, email, and phone number
Contains all active signing and network certs for the organisation
Contains all revoked signing and network certs for the organisation
A link to the OB registries terms of service page
The SSA header MUST comply with [RFC7519].
MUST be set to JWT
MUST be set to ES256 or PS256
The kid will be kept the same as the "x5t" parameter. (X.509 Certificate SHA-1 Thumbprint) of the signing certificate.
The elements defined in the software statement will consist of the following values.
Note that there are inconsistent applications of booleans or "Active" strings in the current data model.
Note that there are inconsistent applications of status flags case sensitivity.
A TPP MAY use automated client registration to submit an SSA to an ASPSP in exchange for client credentials for use as a client against an OAuth 2.0 Authorization Server. It is RECOMMENDED for ASPSPs to support the automated client registration mechanism.
ASPSPs MUST NOT accept client registration requests that do not contain a valid SSA. Requests that pass validation criteria SHOULD result in the ASPSP populating client security characteristics from the metadata within the SSA and client registration requests issuing a registration response.
To support onboarding through APIs, the ASPSP must provide:
A service to validate and process the Request JWT and the SSA JWT contained within supporting both PS256 and ES256 alg types
A service to create and return client credentials based on the security characteristics obtained from the metadata
Storing the the Software Statement ID from the SSA against the client and validating the TPP, App, and SSID.org_jwks_endpoint
The TPP must only present the SSA to an ASPSP over a mutually authenticated TLS channel using a certificate issued by the OB. In this case, the combination of possession of the SSA, the possession of private keys referenced in the SSA and ability to present it over a channel that can be validated as belonging to the same TPP organization, is a strong barrier for attackers. Unlike RFC7591 the client registration request will be of type JWT where the registration request itself is a signed jwt.
Client Registration Endpoint
If an ASPSP supports automated client registration, the ASPSP MUST operate an [RFC7591] compliant registration endpoint.The client registration endpoint MUST be protected by transport-layer security (TLS 1.2 or better)The transport layer MUST be mutually authenticated using certificates chaining to the OpenBanking certificate authorityThe ASPSP registration endpoint MUST accept HTTP POST messages with request parameters encoded in the entity body using the "application/jwt" content-type.The ASPSP registration endpoint SHOULD accept registration attempts from any mutually authenticated channel whose certificate chains to the OpenBanking certificate authority and is not revoked.
Prior to issuing a client registration response, the ASPSP MUST perform the following checksThe ASPSP SHOULD check whether the TPP that initiated the TLS connection is the same TPP as listed in the SSA.In the case where a gateway or other piece of infrastructure pre-terminates the MATLS channel in front of the registration endpoint, the certificate used to initiate the connection or some part of that certificate (such as DN & Issuer) SHOULD be made available to the ASPSP for validation against the claims in the SSA.The registration request MUST be signed with a key contained in the JWKS referenced in the SSA included with the request. This ensures that a holder-of-key proof-of-possession is performed proving that the TPP app was the originally intended recipient of the SSA when the OB issued it.The SSA MUST be validated according to [RFC7519], including validation of the signature and validity window.
JWT signature must be validated, this involves retrieving the jwks keyset for both the OB and the TPP. The OB keystore location will be published as part of the directory specification, The TPP's will be included in the software statement.
The SSA's Lifetime will be short, typically less than 10 minutes. TPPs will be able to retrieve SSAs from OB using client_credentials grant so there should be no need for a SSA to be long lived.
Supported extensions to RFC7591
Section for the support sections / profile enhancements on RFC7591 e.g OIDC client reg profile, reg profile enhancments for mtls token end point auth
Client Registration Request
To register as a client at an ASPSP, the TPP sends an HTTP POST to the ASPSP registration endpoint.The request MUST be presented in the format of a [RFC7519] compliant JWT.The request MUST use the HTTP POST method, using the application/jwt method. * The JWT MUST be signed using algorithms specified in [FAPI-RW] Section 8.6.
The client registration request MUST contain the following claims in the JWT payload unless designated as Optional. The TPP MAY add additional claims to the JWT payload. The ASPSP MAY ignore claims not in the chart below. If a claim name matches a specified claim in any of [RFC7519], [RFC7591], or [FAPI], the usage must also match the specification.
Request Issuer (The TPP)
Time of issuance of request
Request Expiration time
Request audience (The ASPSP)
Registered URIs the TPP will use to interact with the ASPSP AS
MUST match or be a subset of the software_redirect_uris claim in the SSA
Specifies which token endpoint authentication method the TPP wants to use
private_key_jwt : if requested the OP should extract the TPPs JWKS location from the software statement assertion included.
A JSON array specifying what the TPP can request to be supplied to the token endpoint as exchange for an access token
A JSON array specifying what the TPP can request to be returned from the ASPSP authorisation endpoint.
ASPSPs MAY reject anything other thancode
OB Organisation ID
If specified, the software_id in the request MUST match the software_id specified in the SSA. ASPSPs can choose to allow multiple registrations for a given software client name and may take the software_id from either the SSA or the TPP as a hint only.
scopes the client is asking for (if not specified, default scopes are assigned by the AS)
Minimum scope should be openid + whatever scopes are appropriate for the softwares PSD2 Role.
SSA issued by OpenBanking identifier
web or mobile
MUST bewebif specified.
Algorithm which the TPP expects to sign the id_token, if an id_token is returned.
Supported values MUST comply with [FAPI-RW] Section 8.6.
Algorithm which the TPP expects to sign the request object if a request object will be part of the authorization request sent to the ASPSP.
Supported values MUST comply with [FAPI-RW] Section 8.6.
SUPPORTED TOKEN ENDPOINT AUTHENTICATION METHODS
The TPP MUST choose one of the following token endpoint authentication methods:
Private Key JWT AuthenticationA TPP choosing to use the private_key_jwt method to authenticate to the token endpoint MUST set the value of the token_endpoint_auth_method toprivate_key_jwtas specified by [OIDC] Section 9, and [RFC7523].
Mutual TLS Client AuthenticationA TPP choosing to register Mutual TLS as the client authentication method MUST set the following client metadata in the registration request:token_endpoint_auth_methodMUST be set totls_client_authThe client metadata parametertls_client_auth_dnMUST be included in the registration request * The content of thetls_client_auth_dnclaim MUST contain the DN of the certificate that the TPP will present to the ASPSP token endpoint.
HTTP Basic Client AuthenticationA TPP choosing to use HTTP Basic Authentication method MUST set the token_endpoint_auth_method claim in the registration request toclient_secret_basicas per [rfc6749] section 2.3.1.
HTTP POST Client AuthenticationA TPP choosing to use HTTP Basic Authentication method MUST set the token_endpoint_auth_method claim in the registration request toclient_secret_postas per [rfc6749] section 2.3.1.
SUPPORTED GRANT TYPES
The TPP MUST specify one or more of the following values in the grant_types claim. Values MUST be encoded as a JSON array. ASPSPs MAY reject anything other thanclient_credentialsorauthorization_code.authorization_coderefresh_token*client_credentials
SUPPORTED RESPONSE TYPES
A TPP MAY specify response_types in the request. Values MUST be encoded as a JSON array. In the case this value is omitted, and any grant type that utilizes the authorisation endpoint is also specified, the default response_types array contains the single value ofcode. ASPSPs SHOULD supportcode id_tokenand MAY supportcode. Supported response_types include:codecode id_token
Supported Request URIs
The TPP MAY specify a JSON array of [RFC3986] compliant redirect URIs in the request using the redirect_uris metadata element. Every value in the redirect_uris JSON array MUST adhere to the following rules: * The URI MUST use the https scheme * The URI MUST NOT contain a host with a value of localhost * The URI MUST exactly match a URI within the software_redirect_uris element of the SSA as described in Section 6.2.1 of [RFC3986] (Simple String Comparison). If the request_uris metadata element is omitted from the request, the entire contents of the software_redirect_uris element in the SSA are considered to be requested by the TPP.
Some client metadata may be communicated via the software statement (which is embedded in the onboarding request), other metadata could be directly asserted by the TPP as part of the onboarding request. Note that additional metadata values are defined in both RC7591 and in thehttp://openid.net/specs/openid-connect-registration-1_0-29.html#IANAspecification.
OPs MAY NOT support optional values listed below that are asserted by the TPP.
OPs MAY NOT adopt values asserted by the TPP that are also contained in the software statement
OPs SHALL reject requests if the requested configuration is not supported by the OP. e.g token_endpoint_auth_method requested should match one listed on the well-known configuration endpoint.
Registration Request Validation
An ASPSP MUST return an error response if any of the following requirements are not met: - The registration request assertion MUST contain a software statement attribute as client metadata. - The signature of the software statement assertion MUST validate against the OpenBanking JWKS or JWKS URI distributed and validated out of band of the current registration request - The signature of the registration request assertion MUST successfully validate against the JWKS URI specified in thesoftware_jwks_endpointattribute of the software statement assertion (SSA). - If the request assertion specifies aredirect_urismetadata element, the array contents MUST match or be a subset of thesoftware_redirect_urisclaim in the SSA. - If the request assertion specifies asoftware_idmetadata element, that value MUST match thesoftware_idelement in the SSA.
Certificate Based TLS Validation
As described in [RFC7515] section 4.1.4 all OpenBanking Ltd ecosystem certificates will be issued as X.509 certificates that can be uniquely identified in a JWKS key store by the keyid. The format of the keyid will be aligned to the x5t parameter of the certificate from which the key is extracted as documented in [RFC7515] section 4.1.8.
An ASPSP MUST return an error response if any of the following requirements are not met:
The transport layer negotiated by the TPP MUST be mutually authenticated.
The client TLS certificate SHOULD chain to a certificate located in the SSA 'org_jwks_endpoint' attribute.
The client TLS certificate must contain the following attributes:
The Subject DN MUST contain the commonName (CN) attribute and organisationUnit (OU) of the certificate.
The CN attribute of the certificate MUST match thesoftware_idspecified within the SSA.
The OU attribute of the certificate MUST match theorg_idspecified within the SSA.
The Issuer DN MUST be validated ensuring that the issuer was the appropriate Open Banking CA for the environment.
Client Registration Response
At the time that the ASPSP finishes evaluation of the request, the ASPSP MUST return a client registration response to the TPP that reflects the final ASPSP client onboarding decision.
Successful Client Registration Response
In the case where the ASPSP makes a positive determination and creates a client, a Client Information Response MUST be returned to the the TPP conforming to Section 3.2.1 of [RFC7591]. The parameters returned in the response will vary depending on which token endpoint authentication method was specified in the request.
In the case where the ASPSP makes a negative determination and refuses to create a client, the ASPSP MUST return a client registration error response to the TPP conforming to Section 3.2.2 of [RFC7591].
EXAMPLE CLIENT REGISTRATION ERROR RESPONSE
HTTP/1.1 400 Bad Request
"error_description": "Some actionable reason why an ASPSP might reject a valid SSA"
Manual Client Registration
An ASPSP MAY choose to offer a developer web portal for the purposes of client registration. If an OpenBanking-related web portal is offered, the ASPSP portal MUST act as a [SAML2] or [OIDC] compliant relying party to the OpenBanking Directory, where the PTC will be strongly authenticated.
Single Sign-on Configuration
The OpenBanking Directory Single Sign-on service MUST
Act as a [FAPI] compliant OpenID Connect Identity Provider in the Identity Provider role for valid ASPSPs.
Act as a [SAML2] Identity Provider compliant to OB supported profiles
OIDC Available Claims
Is this user associated with at least one TPP in the OpenBanking directory as either a Primary Technical Contact or �Secondary Technical Contact
Has this account been verified by / through OB processes necessary to achieve LoA2 certification of the identity associated with the user credentials
Is this user associated with at least one ASPSP in the OpenBanking directory as either a Primary Technical Contact or �Secondary Technical Contact
Unique Identifier for the Authenticated User
Unique Identifier for the Authenticated User
Active Inactive flag
A contact phone number (mobile) for the user also used as a second means for a authentication during password resets
Surname or Family name
Firstname or Given Name
Display or complete name string
A list of the TPP org_id's that this user is associated with in either a PTC or STC capacity
A list of the ASPSPS org_id's that this user is associated with in either a PTC or STC capacity