Version Control

Version	Date	Author	Comments
v1.0.0	14 Jul 2017	Open Banking Read/Write API Team	Published
Implementer's Draft v1.0.0	28 Jul 2017	Open Banking Read/Write API Team	Renamed to Implementer's Draft. Client Registration section moved to OB Directory Specification
Implementer's Draft v1.0.1	31 Jul 2017	Open Banking Read/Write API Team	Recreating document from up to date sub sections. Clarifications to Implementation Guide Enhanced Payments API Sequence Diagram to improve readability Enhanced Accounts API Sequence Diagram to improve readability and add in the GET and DELETE flows for Account Requests Removing the need to repeat the API scopes when the exchanging of an Authorization Code for an Access Token for Payments and Accounts API requests in the Sequence Diagram and example HTTP Requests
Implementer's Draft v1.1.0	29 Sep 2017	Open Banking Read/Write API Team	Reflecting changes to the R/W API specifications for v1.1: Updated Account Identification SchemeName and structure from BBAN to SortCodeAccountNumber Corrected -00:00 timezone format to +00:00 Updated format for fields within Meta and Links sections to upper camel case Corrected "AwaitingAuthentication" to "AwaitingAuthorisation” in non-normative example Removed x-jws-signature headers from non-normative examples Errata to add redirect_uri to header for the Request : Access Token Request using Authorization Code
Implementer's Draft v1.1.1		Open Banking Read/Write API Team	Reflecting errata updates resultant from live proving Authorisation servers to provide a discovery endpoint over tls not ma-tls and via a browser acceptable root. TDA Decision 117 Removing duplicate references to FAPI Read Write or Read specifications. Adding explicit line number references
Implementer's Draft v1.1.2		Open Banking Read/Write API Team	Reflecting errata updates resultant from live proving and errata issued from the OIDF Financial API Working Group Part 1: clarify that the returned list of scopes should be those granted Part 2: Require redirect_uri to be inside signed request object Allow more ciphers between authorisation server & user's browser #131: client_id supplied in request body should match the one supplied elsewhere TDA Decision 118 Now includes embedded version of profile from Open ID Foundation's Bitbucket repository (rather than duplicating content) Updated examples to reflect correctly namespaced intent ids

Please Note

The MASTER location for this profile is located here: https://bitbucket.org/openid/obuk/src/4630771db004da59992fb201641f5c4ff2c881f1/uk-openbanking-security-profile.md?at=master&fileviewer=file-view-default

Version Control is located here: https://bitbucket.org/openid/obuk/commits/all. All changes are tracked as GIT commits for 100% transparency and visibility. Ideally comments, issues and pull requests will raised against the OIDF git repository however comments raised below as comments or on feedback pages will be responded too and incorporated during a transition period.

The tagged version in Bitbucket which corresponds to this specification version is included below.

UK Open Banking OIDC Security Profile

Security Architecture

OAuth 2.0, OIDC and FAPI

OAuth 2.0 will be the foundational framework for API Security in OpenBanking. The process of requesting a token is standards based - the question is, which standards. OAuth 2.0 itself is a framework which can be deployed in many ways, some of them completely incompatible with financial models. In order to securely use the OAuth 2.0 framework, a profile must exist by which both TPP and ASPSP participants are certified to have correctly configured their clients and servers. The Financial API working group in the OpenID Foundation has created a draft standard for configuration of financial grade API security regimes, and it is strongly recommended that OpenBanking follow that standard. If any FAPI-compliant vendor can participate in the OpenBanking ecosystem, it means that vendors can work to the standard and reach many customers, rather than having to create different solutions for different banking platforms.

Consuming PSU owned Resources from an ASPSP

Overview

See: http://openid.net/specs/openid-connect-core-1_0.html#JWTRequests (OpenID Connect Core Section 6)

The OpenID Connect Request object uses exactly the same claims object for specifying claim names, priorities, and values, however if the request object is used, the claims object becomes a member in an assertion that can be signed and encrypted, allowing the ASPSP to authenticate the request from the TPP and ensure it hasn't been tampered with. The OpenID Connect request object can either be passed as a query string parameter, or can be referenced at an endpoint that could theoretically be protected by MATLS. OpenBanking, in conjuction with major IAM vendors, is ruling out the use of JWT Request objects by reference due a number of delivery risks and remaining security concerns.

In addition to specifying a ticket, the TPP can optionally require a minimum strength of authentication context or request to know how long ago the user was actually authenticated. Multiple tickets could be passed if necessary. Everything is fully specified. Vendors who implement this feature are not creating a one-off proprietary feature, they are simply supporting the OpenID Connect standard.

Full accountability is available as required by all participants. Not only can the ASPSP prove that they received the original request from the TPP, but the TPP can prove that the access token that comes back was the token that was intended to be affiliated to this specific payment.

Hybrid Flow Request with Intent Id

This section describes parameters that should be used with an hybrid grant flow request so that an intent id can be passed from the TPP to an ASPSP.

Prior to this step,

The TPP would have already registered an intent with an ASPSP. This is achieved by using one of the account information or payment initiation APIs.
The ASPSP would have responsded with an intent id.

Hybrid Grant Parameters

Minimum Conformance

Overview

This section describes the bare minimum set of Authorization Request parameters that an ASPSP must support for the Jan, 2018 release. The technical definitive reference is specified in OpenID Connect Core Errata 1 Section 6.1 (Request Object). All standards and guidance MUST be followed as per the specification.

All ASPSPs MUST support the issuance of OIDC ID Tokens, a TPP MAY request that an ID token is issued.

Parameter	Open Banking	Notes
response_type	Required	OAuth 2.0 requires that this parameter is provided. Value is set to 'code id_token', 'code id_token token' or 'code' TPPs MUST provide this parameter and set its value to one of the three above depending on what the ASPSP supports as described in its well-known configuration endpoint. The values for these parameters MUST match those in the Request Object, if present. Note: risks have been identified with "code" flow that can be mitigated with hybrid flow, the OpenBanking Profile allows ASPSPs to indicate what grant types are supported using the standard well-known configuration endpoint. RP's must take care in valdiating that code swap attacks have not been attempted.
client_id	Required	TPPs MUST provide this value and set it to the client id issued to them by the ASPSP to which the authorization code grant request is being made.
redirect_uri	Required	TPPs MUST provide the URI to which they want the resource owner's user agent to be redirected to after authorization. This MUST be a valid, absolute URL that was registered during Client Registration with the ASPSP.
scope	Required	TPPs MUST specify the scope that is being requested. At a minimum the scope parameter MUST contain openid The scopes MUST be a sub-set of the scopes that were registered during Client Registration with the ASPSP.
state	Recommended	TPPs MAY provide a state parameter. The parameter may be of any format and is opaque to the ASPSP. If the parameter is provided, the ASPSP MUST play-back the value in the redirect to the TPP OPs SHOULD include the s_hash
request	Required	The TPP MUST provide a value for this parameter. The parameter MUST contain a JWS that is signed by the TPP. The JWS payload MUST consist of a JSON object cotntaining a request object as per OIDC Core 6.1. The request object MUST contain a claims section that includes as a minimum openbanking_intent_id: that identifies the intent id for which this authorisation is requested The intent id MUST be the identifier for an intent returned by the ASPSP to TPP that is initiating the authorisation request. acr_values TPPs MAY provide a space-separated string that specifies the acr values that the Authorization Server is being requested to use for processing this Authentication Request, with the values appearing in order of preference. The values MUST be one or both of: urn:openbanking:psd2:sca: To indiciate that secure customer authentication must be carried out as mandated by the PSD2 RTS urn:openbanking:psd2:ca: To request that the customer is authenticated without using SCA (if permitted) Subject to review from Government Digital Services / Cabinet Office Inside an ID Token. The request object MAY* contain claims to be retrieved via the UserInfo endpoint only if the endpoint is made available and listed on the well known configuration endpoint on the authorisation server. The request object MAY contain additional claims to be requested should the ASPSPs Authorization Server support them, these claims will be listed on the OID Well Known configuration endpoint.

Example for minimum conformance

Examples are non-normative

HTTP Request

GET /authorize?
response_type=code%20id_token
&client_id=s6BhdRkqt3
&state=af0ifjsldkj&
&scope=openid
&nonce=n-0S6_WzA2Mj
&redirect_uri=https://api.mytpp.com/cb
&request=CJleHAiOjE0OTUxOTk1ODd.....JjVqsDuushgpwp0E.5leGFtcGxlIiwianRpIjoiM....JleHAiOjE0.olnx_YKAm2J1rbpOP8wGhi1BDNHJjVqsDuushgpwp0E

Request JWS (Without Base64 encoding)

Note that "essential" is an optional required OPTIONAL. Indicates whether the Claim being requested is an Essential Claim. If the value is true, this indicates that the Claim is an Essential Claim. For instance, the Claim request:

  "auth_time": {"essential": true}

can be used to specify that it is Essential to return an auth_time Claim Value.If the value is false, it indicates that it is a Voluntary Claim. The default is false.By requesting Claims as Essential Claims, the RP indicates to the End-User that releasing these Claims will ensure a smooth authorization for the specific task requested by the End-User. Note that even if the Claims are not available because the End-User did not authorize their release or they are not present, the Authorization Server MUST NOT generate an error when Claims are not returned, whether they are Essential or Voluntary, unless otherwise specified in the description of the specific claim. OIDC Core

{
    "alg": "RS256",
    "kid": "GxlIiwianVqsDuushgjE0OTUxOTk"
}
.
{
   "aud": "https://api.alphanbank.com",
   "iss": "s6BhdRkqt3",
   "response_type": "code id_token",
   "client_id": "s6BhdRkqt3",
   "redirect_uri": "https://api.mytpp.com/cb",
   "scope": "openid payments accounts",
   "state": "af0ifjsldkj",
   "nonce": "n-0S6_WzA2Mj",
   "max_age": 86400,
   "claims":
    {
     "userinfo":
      {
       "openbanking_intent_id": {"value": "urn:alphabank-intent-58923", "essential": true}
      },
     "id_token":
      {
       "openbanking_intent_id": {"value": "urn-alphabank-intent-58923", "essential": true},
       "acr": {"essential": true,
                "values": ["urn:openbanking:psd2:sca",
                     "urn:openbanking:psd2:ca"]}}
      }
    }
}
.
<<signature>>

id_token returned - Sub being populated with an EphemeralId of the IntentId - Non Normative

{
  "alg": "RS256",
  "kid": "12345",
  "typ": "JWT"
}
.
{
   "iss": "https://api.alphabank.com",
   "iat": 1234569795,
   "sub": "urn-alphabank-payment-58923",
   "acr": "urn:openbanking:psd2:ca",
   "openbanking_intent_id": "urn-alphabank-payment-58923",
   "aud": "s6BhdRkqt3",
   "nonce": "n-0S6_WzA2Mj",
   "exp": 1311281970,
   "s_hash": "76sa5dd",
   "c_hash": "asd097d"
  }
.
{
<<Signature>>
}

id_token returned - Identity Claims and IntentId With sub being populated with an UserIdentifier - Non Normative

{
  "alg": "RS256",
  "kid": "12345",
  "typ": "JWT"
}
.
{
   "iss": "https://api.alphabank.com",
   "iat": 1234569795,
   "sub": "ralph.bragg@raidiam.com",
   "acr": "urn:openbanking:psd2:sca",
   "address": "2 Thomas More Square",
   "phone": "+447890130559",
   "openbanking_intent_id": "urn-alphabank-payment-58923",
   "aud": "s6BhdRkqt3",
   "nonce": "n-0S6_WzA2Mj",
   "exp": 1311281970,
   "s_hash": "76sa5dd",
   "c_hash": "asd097d"
  }
.
{
<<Signature>>
}

ID Token Claims Details: Where appropriate please follow the JWT Good Practice Guides http://self-issued.info/docs/draft-sheffer-oauth-jwt-bcp-00.html#rfc.section.3.1

Field	Definition	Notes	Value(s)	Required by Protocol	Required by OBIE
iss	Issuer of the token	Token issuer will be specific to the business	https://private.api.hsbc.com https://private.api.firstdirect.com https://private.api.marksandspencer.com	Yes	Yes A JSON string that represents the issuer identifier of the authorization server as defined in RFC7519. When a pure OAuth 2.0 is used, the value is the redirection URI. When OpenID Connect is used, the value is the issuer value of the authorization server.
sub	Token subject identifier	A unique and non-repeating identifier for the subject i.e the customer. couple of rules: It needs to be the same when created by the authorisation and Token endpoints during the Hybrid flow.	Non Identity Services Providers: Use the Intent/Consent ID for this field. Identity Services Providers: Value at the discretion of the OP's.	Yes	Yes
openbanking_intent_id	Intent ID of the originating request	A unique and non-repeating identifier containing the intentid.	Use the Intent/Consent ID for this field.	No	Yes - it's acknowledged that this field may duplicate the value in "sub" for many providers.
aud	Audience that the ID token is intended for	OpenID Connect protocol mandates this MUST include the client ID of the TPP.	Should contain the ClientID of the TPP's OAuth Client.	Yes	Yes - as per FAPI RW / OpenID Standard.
exp	Token expiration date/time		Expressed as an epoch i.e. number of seconds from 1970-01-01T0:0:0Z as measured in UTC. RFC7519.	Yes	Yes The validity length will be at the discretion of the Banks provided that it does not impact the functionality of the APIs. For example, an expiry time of 1 second is insufficient for all Resource Requests.
iat	Token issuance date/time		Expressed as an epoch i.e. number of seconds from 1970-01-01T0:0:0Z as measured in UTC. RFC7519.	Yes	Yes
auth_time	Date/time when End User was authorised	This field is Required when the max_age request is made or max_age is included as an essential claim. In order to be compliant with the protocol we therefore need to support it.	Expressed as an epoch i.e. number of seconds from 1970-01-01T0:0:0Z as measured in UTC.	Case-specific	Case-Specific
nonce	Used to help mitigate against replay attacks	Value is passed in as a Request parameter. If present it must be replayed in the ID token		Case-Specific	Required by FAPI Read Write (Hybrid explicitly required - required by OIDC Core for Hybrid Flow). Hybrid Flow support is optional in the OB Security Profile.
acr	Authentication Context Class Reference	An identifier that qualifies what conditions the authentication performed satisfied. The acr SHOULD correspond to one of the values requested by the acr_values field on the request however even if not present on the request the aspsp should populate the acr with a value that attests that the aspsp performed or NOT performed an appropriate level of authentication such that the aspsp believes it has met the requirement for "Strong Customer Authentication".	The values to be provided will be to urn:openbanking:psd2:ca or urn:openbanking:psd2:sca. To cover the exemptions cases of PSD2 the PISP / AISP must have a way to request that a Bank NOT perform SCA for some requests. It’s entirely within the banks gift to ignore the requested ACR_VALUES however the Bank must reply with what level of AuthN was performed. (Once RTS comes into affect).	No	Yes Caveated: As RTS is not signed off and will not be delivered by initial go-live aspsps do not have to provide a response value. Aspsps that do not wish to provide this as a claim should remove it from the well-known configuration endpoint. As per OIDC Core, marking a claim as "essential" and an ASPSP can not fulfill it then an error should not be generated.
amr	Authentication Methods References	The methods that are used in the authentication. For example, this field might contain indicators that a password was supplied or OTP initiated.	Note – industry direction is to consolidate on https://datatracker.ietf.org/doc/draft-richer-vectors-of-trust. so expect this field to be replaced shortly. AMR doesn’t give the flexibility to address all the actual particulars of both the authn and the identity that sits behind it.	No	No requirement to specify as it is to be soon superseded by Vectors of Trust.
azp	Authorized party	OPTIONAL. Authorized party - the party to which the ID Token was issued. If present, it MUST contain the OAuth 2.0 Client ID of this party. This Claim is only needed when the ID Token has a single audience value and that audience is different than the authorized party. It MAY be included even when the authorized party is the same as the sole audience. The azp value is a case sensitive string containing a StringOrURI value.	OB N/A	No	No specific requirement from OB.
s_hash	State Hash Value	May include state hash, `s_hash`, in the ID Token to protect the `state` value;	Its value is the base64url encoding of the left-most half of the hash of the octets of the ASCII representation of the state value, where the hash algorithm used is the hash algorithm used in the `alg`Header Parameter of the ID Token's JOSE Header. For instance, if the alg is HS512, hash the code value with SHA-512, then take the left-most 256 bits and base64url encode them. The `s_hash`value is a case sensitive string.	No	Recommended by OB
at_hash	Access Token Hash Value	Access Token hash value.	Its value is the base64url encoding of the left-most half of the hash of the octets of the ASCII representation of the access_token value, where the hash algorithm used is the hash algorithm used in the alg Header Parameter of the ID Token's JOSE Header. For instance, if the alg is RS256, hash the access_token value with SHA-256, then take the left-most 128 bits and base64url encode them. The at_hash value is a case sensitive string.	Conditional	As per Hybrid Flow (OIDC Core) - Yes If the ID Token is issued from the Authorization Endpoint with an access_token value, which is the case for the response_type value code id_token token, this is REQUIRED; otherwise, its inclusion is OPTIONAL.
c_hash	Code hash value.	Code Hash Value	Its value is the base64url encoding of the left-most half of the hash of the octets of the ASCII representation of the code value, where the hash algorithm used is the hash algorithm used in the alg Header Parameter of the ID Token's JOSE Header.	Conditional	As per Hybrid Flow (OIDC Core) - Yes. If the ID Token is issued from the Authorization Endpoint with a code, which is the case for the response_type values code id_token and code id_token token, this is REQUIRED; otherwise, its inclusion is OPTIONAL.

JSON Security Suite Information v1.0

General Guidance for JWT Best Practice: To Be Followed Where Appropriate

http://self-issued.info/docs/draft-sheffer-oauth-jwt-bcp-00.html#rfc.section.3.1

Algorithms to be supported: All Asymmetric Algorithms listed below

TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384

JWKS Endpoints

All JWKS endpoints will be hosted by OpenBanking Ltd. Upon issuance of a certificate a JWK Set will be created or updated for a given TPP.

All participants should include "kid" and "jku" of the key that was used to sign the payloads. The JKU should be considered a hint only and relying parties should derive and then validate wherever possible the appropriate JWKS endpoint for the message signer.

https://tools.ietf.org/html/draft-ietf-jose-json-web-signature-41#section-4.1

example:

https://keystore.openbanking.org.uk/tpp/12345678.jwks

As certificates are added and removed by Participant Technical Contacts the jwks endpoint will be updated automatically.

General outline for creating a JWS

Step 1: Select the certificate and private key that will be used for signing the JWS

As the JWS is used for non-repudiation, it MUST be signed using one of JWS issuer's private keys.

The private key MUST have been used by the issuer to get a signing certificate issued from OB.

The signing certificate MUST be valid at the time of creating the JWS.

Step 2: Form the JOSE Header

The JOSE header is a JSON object consisting of three fields (claims):

Claim

RFC 7515 Standard ?

Required ?

Description

alg

Yes

Mandatory

The algorithm that will be used for signing the JWS.

The list of valid algorithms is here https://tools.ietf.org/html/rfc7518#section-3.1.

This MUST be an algorithm that support asymmetric encryption.

OB MAY limit this down further.

kid

Yes (optional)

Mandatory

   The "kid" (key ID) Header Parameter is a hint indicating which key
   was used to secure the JWS.

This MUST match the certificate id of the certificate selected in step 1.

The receiver SHOULD use this value to identify the certificate to be used for verifying the JWS.

Step 3: Form the payload to be signed

The JSON payload to be signed must have the following claims:

Claim

Required ?

Description

iss

Mandatory

The issuer of the JWS.

This MUST match the dn of the certificate selected in step 1.

The payload to be signed is computed as:

payload = base64Encode (JOSEHeader) + "." + base64Encode( json)

Where:

JOSEHeader: is the header created in Step 2 and

json: is the message the original data to be sent

Step 4: Sign and encode the payload

The signed payload is computed as:

signedAndEncodedPayload = base64Encode (encrypt( privateKey, payload))

Where:

privateKey: is the private key selected in step 1

payload: is the payload computed in Step 3

encrypt: Is an encryption function that implements the `alg` identified in Step 2.

Step 5: Assemble the JWS

The JWS is computed as

JWS = payload + "." + signedAndEncodedPayload

Where:

payload: is the payload computed in Step 3

signedAndEncodedPayload: is the signed element computed in Step 5.

Implementation Guide

Overview

This page provides an implementation perspective of the OB Security Profile aligned to the accepted OB Read/Write APIs for Payments and Accounts Specifications.

Specified Behaviour

The implementation of both the Payments and Accounts API are based on the following known configurations:

Client Types

As per the OAuth 2.0 specification, the Confidential Client Type is illustrated for both Accounts and Payments API as it has the ability to maintain its own credentials.

Grant Types

OIDC Hybrid Flow (response_type=code id_token)

Both the Payments and Accounts APIs illustrate the use of request_type=code id_token for the OIDC Hybrid Flow implementation.
The ASPSP may optionally choose to return Refresh Tokens for the Hybrid Flow when issuing an Access Token

Client Credentials Grant Type using multiple scopes (scope=accounts payments)

The Client Credentials Grant Type is used across both Payments and Account APIs only when the TPP (AISP/PISP) requires an Access Token (on behalf of itself) in order to access a Payment or Accounts API resource e.g.
- Payments:
```
POST /payments
GET /payment-submissions/{PaymentSubmissionId}
```
- Accounts:
```
POST /account-requests
```
Where an ASPSP enables the same Confidential Client (ClientId) access to both Payments and Accounts APIs, a TPP may therefore choose to request for either a single scope e.g. accounts or for multiple scope(s) e.g. accounts payments as the TPP may want to use the same Access Token across both APIs.
Only valid API scopes will be accepted when generating an Access Token (accounts payments).
Access tokens generated by a Client Credentials grant may not return any refresh tokens (as per the OAuth 2.0 specification)

Access Tokens

For the Payments and Accounts APIs, the Access Token must be obtained within a Secure, Server Side Context between the TPP (AISP / PISP) and the ASPSP.
Access Tokens must be validated by the TPP (AISP/PISP) as outlined within the OIDC Errata 1 Specification

Refresh Tokens

ASPSPs may optionally return a Refresh Token when an Authorization Request is successfully processed at the Token endpoint. The Hybrid flow supports the provisioning of Refresh Tokens.
The Accounts API implementation below cites an example for AISPs requesting a Refresh Token to refresh an expired Access Token prior to invoking the /accounts resource.
Refresh Tokens must be validated as outlined in the OIDC Errata 1 Specification

ID Tokens

ID Tokens must be validated by the TPP (AISP/PISP) as outlined within the OIDC Errata 1 Specification
TPPs must use the openbanking_intent_id claim to populate and retrieve the IntentID (PaymentID for Payments API and AccountRequestId for the Accounts API) for any required validation.
The full set of claims that can be represented within an ID Token are documented in the Request Object and ID Token Section of the Security Profile.

Authorization Codes

Authorization Codes must be validated by the TPP (AISP/PISP) as outlined within the OIDC Errata 1 Specification

Un-Specified Behaviour

The implementation of both the Payments and Accounts API are un-specified for the following configurations:

Client Types

As per the OAuth 2.0 specification, the Public Client Type has not been illustrated for both Payments and Accounts APIs.

Grant Types

OIDC Hybrid Flow (response_type=code id_token token or response_type=code token)

Forces an Access Token to be returned from the ASPSP Authorization endpoint (instead of a token endpoint). This is not illustrated in the Payments and Accounts API Specifications.

OIDC Implicit Flow (response_type=id_token token or response_type=id_token)

The Implicit Flow does not authenticate the Client that is invoking the request. This is not illustrated in the Payments and Accounts API Specifications.

Client Credentials Grant Type(scope=openid email profile address phone)

Requesting OIDC specific scopes or any un-specified scopes when using the Client Credentials grant.

Validity Lengths (Authorization Code, Access Token, ID Token, Refresh Token)

These are to be managed in the competitive space; Each ASPSP's Authorization / Resource Server will be configured independently to comply with internal ASPSP Security Policies and Guidelines. The Accounts and Payments API Specifications do not mandate validity lengths.

Authorization Code

OAuth 2.0 Specification suggests an Authorization Code should be short lived to a maximum of 10 minutes. Any codes exceeding this limit to be rejected.

ID Token

ID Token claims (exp and iat) determine its validity.
Returned with the Authorization Code when the Hybrid flow (code id_token) is initiated.

Access Token

The expires_in attribute returned by the Authorization Server when an Access Token is generated determines its validity.
Access Tokens are generally short lived, and where they expire, are then exchanged for another using a longer lived Refresh Token.
Refer to Section 16.18 of the OIDC Specification - Lifetimes of Access Tokens and Refresh Tokens.

Refresh Token

The expires_in attribute returned by the Authorization Server when a Refresh Token is generated determines its validity.
Refresh Tokens are generally longer lived in comparison to Access Tokens.
Refer to Section 16.18 of the OIDC Specification - Lifetimes of Access Tokens and Refresh Tokens.

Success Flows

Payment API Specification

The sequence diagram below highlights the OAuth 2.0 Client Credentials Grant and OIDC Hybrid flow that are used by the Payments API.

Payment Initiation with Client Credentials Grant Type and OIDC Hybrid Flows

participant PSU
participant PISP
participant ASPSP Authorisation Server
participant ASPSP Resource Server
   
autonumber 1
    
PSU -> PISP: Establish TLS 1.2
    
note over PSU, ASPSP Resource Server
Step 1: Request payment initiation
end note
PSU -> PISP: Send payment initiation request
     
note over PSU, ASPSP Resource Server
 Step 2: Setup single payment initiation
end note
    
    PISP <-> ASPSP Authorisation Server: Establish TLS 1.2 MA
    note left of PISP
        Client Credentials Grant
    end note
    PISP->ASPSP Authorisation Server: POST /token (client authentication credentials, scope:payments)
    ASPSP Authorisation Server->ASPSP Authorisation Server: Validate client authentication credentials, scope
    ASPSP Authorisation Server->ASPSP Authorisation Server: Validate clientId matches client SSL cert
    ASPSP Authorisation Server -> PISP: HTTP 200 (OK) access-token (scope:payments)
        
    
    PISP <-> ASPSP Resource Server: Establish TLS 1.2 MA
    PISP -> ASPSP Resource Server: POST /payments (access-token - scope:payments)
    ASPSP Resource Server->ASPSP Resource Server: Validate access token
    ASPSP Resource Server->ASPSP Resource Server: Validate scope:payments
    ASPSP Resource Server->ASPSP Resource Server: Validate clientId matches client SSL cert
       
    ASPSP Resource Server->ASPSP Resource Server: Create new payment resource
    ASPSP Resource Server->ASPSP Resource Server: Bind PaymentId with ClientId
    ASPSP Resource Server -> PISP: HTTP 201 (Created),  PaymentId
    
    note right of PISP
        Begin OIDC Hybrid Flow.
        See 6.1.  Passing a Request Object by Value
        See 5.5.  Requesting Claims using the "claims" Request Parameter
        The claims parameter must at least request:
             "id_token": {
       "openbanking_intent_id": {"value": PaymentId, "essential": true},
       "acr": {"essential": true}
      }
      The response object must be signed using the PISP's private key.
    end note
    PISP->PISP: Persist PaymentId
    note right of PISP
        The PISP should store the PaymentId in a manner
        that it can be retrieved again later in the flow in Step 4.
           
        This could be stored in the user session (and retrieved using 'state'
        as a key) or the PSU could use some other unique identifier.
           
        This will be re-retrieved in [43].
           
    end note
    PISP->PISP: Create signed request object with requested Claims (PaymentId)
    PISP -> PSU: HTTP 302 (Found); Location: /authorize,\nredirect-uri, clientId, state, nonce, scope=openid payments,\nresponse-type=code id_token,\nrequest=signed JWT request object - PaymentId)
    
note over PSU, ASPSP Resource Server
 Step 3: Authorize consent
end note
    
PSU -> ASPSP Authorisation Server: HTTP GET /authorize redirect-uri, clientId, state, nonce, scope=openid payments, response-type=code id_token,\nrequest=signed JWT request object - PaymentId
ASPSP Authorisation Server->ASPSP Authorisation Server: Validate clientid, scope
ASPSP Authorisation Server->ASPSP Authorisation Server: Validate redirect-uri for clientId
ASPSP Authorisation Server->ASPSP Authorisation Server: Validate JWT request claim -PaymentId
    note right of ASPSP Authorisation Server
        Validate the request object by using the PISP's public key.
        PISP certificate will be identified using the kid claim
        in the JOSE header of the request object.
           
        Check that the PaymentId belongs to the ClientId that initiated the request.
    end note
ASPSP Authorisation Server<->PSU: Authenticate (Login and consent page)
PSU <-> ASPSP Authorisation Server: SCA if required
PSU <-> ASPSP Authorisation Server: Select debtor account
ASPSP Authorisation Server->ASPSP Authorisation Server: Generate authorization-code, id_token
note right of ASPSP Authorisation Server
    id_token claims:{
    c_hash: 123,
    s_hash: 456
    }
    id_token must be signed using the ASPSP's private key.
    The generation of c_hash is documented in OIDC: 3.3.2.11.  ID Token
    The generation of s_hash is in FAPI R/W spec: Section 5.1
    http://openid.net/specs/openid-financial-api-part-2-wd-02.html#introduction
end note
   
ASPSP Authorisation Server -> PSU: HTTP 302 (Found); Location: redirect-uri (authorization-code, id_token, state)
PSU -> PISP: HTTP GET redirect-uri (authorization-code, id_token, state)
PISP->PISP: Validate signature on id_token
note right of PISP
    Validate the id_token by using the ASPSP's public key.
    ASPSP certificate will be identified using the kid claim
    in the JOSE header of the id_token
end note
PISP->PISP: Validate authorization-code using id_token (c_hash)
PISP->PISP: Validate state using id_token (s_hash)
PISP->PISP: Validate nonce using id_token
    
    
note right of PISP:
    Exchange authorization-code for access token.
end note
PISP <-> ASPSP Authorisation Server: Establish TLS 1.2 MA
PISP -> ASPSP Authorisation Server: HTTP POST /token (client authentication credentials,\nauthorization-code, grant_type, redirect_uri)
    ASPSP Authorisation Server->ASPSP Authorisation Server: Validate clientId matches client SSL cert
    ASPSP Authorisation Server->ASPSP Authorisation Server: Validate client authentication credentials,\nauthorization-code
    ASPSP Authorisation Server->ASPSP Authorisation Server: Generate access-token
    ASPSP Authorisation Server->ASPSP Authorisation Server: Bind access-token to PaymentId
       
ASPSP Authorisation Server -> ASPSP Resource Server: Update Payment Status to AcceptedCustomerProfile
ASPSP Resource Server -> ASPSP Authorisation Server: OK
note right of ASPSP Authorisation Server
    Implementation of how the resource is updated is ASPSP specific. (There is
    no standardised API for this)
end note
   
   
ASPSP Authorisation Server -> PISP: HTTP 200 (OK) access-token (scope:payments)
     
       
note over PSU, ASPSP Resource Server
Step 4: Create payment submission
end note
PISP <-> ASPSP Resource Server: Establish TLS 1.2 MA
PISP->PISP: Retrieve PaymentId
note left of PISP
    Retrieve the PaymentId that was issued in Step 2.
    The method for doing this will depend on how the PISP persisted
    the payment id in [16]
       
end note
   
alt Validate PaymentId in  ID Token
    PISP->PISP: Decode / verify ID Token
    PISP->PISP: Read PaymentId from id_token claim
    PISP->PISP: Compare with PaymentId retrieved in [43]
else Validate PaymentId from UserInfo endpoint
    PISP->ASPSP Resource Server: GET /userInfo (access-token)
    ASPSP Resource Server->ASPSP Resource Server: Validate access-token matches client SSL cert
    ASPSP Resource Server->ASPSP Resource Server: Validate access-token
    ASPSP Resource Server->PISP: HTTP 200 (OK) - UserInfo claim - PaymentId
end
PISP -> ASPSP Resource Server: POST /payment-submissions (access-token - scope:payments) using PaymentId
    ASPSP Resource Server->ASPSP Resource Server: Validate access-token
    ASPSP Resource Server->ASPSP Resource Server: Validate access-token matches client SSL cert
    ASPSP Resource Server->ASPSP Resource Server: Validate scope:payments
    note right of ASPSP Resource Server
        Check binding created in [38]
    end note
    ASPSP Resource Server->ASPSP Resource Server: Ensure access-token is bound to PaymentId
    ASPSP Resource Server->ASPSP Resource Server: Update payment status to AcceptedSettlementInProcess
ASPSP Resource Server -> PISP: HTTP 201 (Created), PaymentSubmissionId
     
note over PSU, ASPSP Resource Server
Step 5: Get payment submission status
end note
     
opt
    PISP <-> ASPSP Resource Server: Establish TLS 1.2 MA
    alt Use active access token to retrieve payment status
        PISP -> ASPSP Resource Server: GET /payment-submissions/{PaymentSubmissionId} (access-token - scope:payments)
        ASPSP Resource Server->ASPSP Resource Server: Validate access-token
        ASPSP Resource Server->ASPSP Resource Server: Validate access-token matches client SSL cert
        ASPSP Resource Server->ASPSP Resource Server: Validate scope:payments
        ASPSP Resource Server->PISP: HTTP 200 (OK), payment-submissions resource
    else Initiate fresh access token via client credentials grant
        note left of PISP
            Client Credentials Grant
        end note
        PISP->ASPSP Authorisation Server: POST /token (client authentication credentials, scope:payments)
        ASPSP Authorisation Server->ASPSP Authorisation Server: Validate client authentication credentials, scope
        ASPSP Authorisation Server->ASPSP Authorisation Server: Validate clientId matches client SSL cert
        ASPSP Authorisation Server -> PISP: HTTP 200 (OK) access-token (scope:payments)
        PISP -> ASPSP Resource Server: GET /payment-submissions/{PaymentSubmissionId} (access-token - scope:payments)
        ASPSP Resource Server->ASPSP Resource Server: Validate access-token
        ASPSP Resource Server->ASPSP Resource Server: Validate access-token matches client SSL cert
        ASPSP Resource Server->ASPSP Resource Server: Validate scope:payments
        ASPSP Resource Server->PISP: HTTP 200 (OK), payment-submissions resource
    end alt
end opt

Client Credentials Grant Type (OAuth 2.0)

Summary

This grant type is used by the PISP in Step 2 to setup a single payment with the ASPSP.

The PISP initiates an Authorization request using valid Client Credentials Grant type and scope(s)
The ASPSP Authorization Server validates the Client Authentication request from the PISP and generates an Access Token response where the request is valid
The PISP uses the Access Token to create a new Payment resource against the ASPSP Resource Server
The ASPSP Resource server responds with the PaymentId for the resource it has created.
The Client Credentials Grant may optionally be used by the PISP in Step 5 to retrieve the status of a Payment or Payment-Submission where no active Access Token is available.

OIDC Hybrid Flow

Summary

The Hybrid flow is the recommendation from the OB Security Profile and the FAPI Specification for R/W. The Hybrid flow prevents IdP mixup attacks as documented by Nat Sakimura - Cut and Paste OAuth 2.0 Attack
This is initiated at the end of Step 2 by the PISP after the PaymentId is generated by the ASPSP and returned to the PISP.
This is used in a redirect across the PSU and ASPSP in Step 3 in order for the PSU to authorize consent with the ASPSP - for the PISP to proceed with the Payment.
This is used across the PISP and ASPSP in Step 4 by exchanging the Authorization Code for an Access Token in order to create the Payment-Submission resource.

Non-Normative HTTP Request and Response Examples

Step 1 - Request Payment Initiation

There are no Requests and Responses against the Payments API in this Step for the PSU, PISP and ASPSP.

Step 2 - Setup Single Payment Initiation

1. PISP obtains an Access Token using a Client Credentials Grant Type. The scope payments must be used. When an Access Token expires, the PISP will need to re-request for another Access Token using the same request below.

Request : Client Credentials using private_key_jwt

Response : Client Credentials

POST  /as/token.oauth2 HTTP/1.1
Host: https://authn.alphabank.com
Content-Type: application/x-www-form-urlencoded
Accept: application/json
grant_type=client_credentials
&scope=payments
&client_assertion_type=
    urn%3Aietf%3Aparams%3Aoauth%3Aclient-assertion-type%3Ajwt-bearer
&client_assertion=eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRw
czovL2p3dC1pZHAuZXhhbXBsZS5jb20iLCJzdWIiOiJtYWlsdG86bWlrZUBleGFtcGxlLmN
vbSIsIm5iZiI6MTQ5OTE4MzYwMSwiZXhwIjoxNDk5MTg3MjAxLCJpYXQiOjE0OTkxODM2MD
EsImp0aSI6ImlkMTIzNDU2IiwidHlwIjoiaHR0cHM6Ly9leGFtcGxlLmNvbS9yZWdpc3Rlc
iJ9.SAxPMaJK_wYl_W2idTQASjiEZ4UoI7-P2SbmnHKr6LvP8ZJZX6JlnpK_xClJswAni1T
p1UnHJslc08JrexctaeEIBrqwHG18iBcWKjhHK2Tv5m4nbTsSi1MFQOlMUTRFq3_LQiHqV2
M8Hf1v9q9YaQqxDa4MK0asDUtE_zYMHz8kKDb-jj-Vh4mVDeM4_FPiffd2C5ckjkrZBNOK0
01Xktm7xTqX6fk56KTrejeA4x6D_1ygJcGfjZCv6Knki7Jl-6MfwUKb9ZoZ9LiwHf5lLXPuy
_QrOyM0pONWKj9K4Mj7I4GPGvzyVqpaZUgjcOaZY_rlu_p9tnSlE781dDLuw

Non-Base64 JWT client_assertion

{
  "alg": "RS256",
  "kid": "12345",
  "typ": "JWT"
}
.
{
  "iss": "s6BhdRkqt3",
  "sub": "s6BhdRkqt3",
  "exp": 1499187201,
  "iat": 1499183601,
  "jti": "id123456",
  "aud": "https://authn.alphabank.com/as/token.oauth2"
}
.
<<signature>>

Content-Length: 1103
Content-Type: application/json
Date: Mon, 26 Jun 2017 15:18:28 GMT
{
    "access_token": "2YotnFZFEjr1zCsicMWpAA",
    "expires_in": 3600,
    "token_type": "bearer",
	"scope":"payments"
}

2. PISP uses the Access Token (with payments scope) from the ASPSP to invoke the Payments API. This example is sourced directly from the Payment API Specification

Request : Payments API

Response : Payments API

POST /payments HTTP/1.1
Authorization: Bearer 2YotnFZFEjr1zCsicMWpAA
x-idempotency-key: FRESCO.21302.GFX.20
x-fapi-financial-id: OB/2017/001
x-fapi-customer-last-logged-time: 2017-06-13T11:36:09
x-fapi-customer-ip-address: 104.25.212.99
x-fapi-interaction-id: 93bac548-d2de-4546-b106-880a5018460d
Content-Type: application/json
Accept: application/json
 
{
  "Data": {
    "Initiation": {
      "InstructionIdentification": "ACME412",
      "EndToEndIdentification": "FRESCO.21302.GFX.20",
      "InstructedAmount": {
        "Amount": "165.88",
        "Currency": "GBP"
      },
      "CreditorAccount": {
        "SchemeName": "SortCodeAccountNumber",
        "Identification": "08080021325698",
        "Name": "ACME Inc",
        "SecondaryIdentification": "0002"
      },
      "RemittanceInformation": {
        "Reference": "FRESCO-101",
        "Unstructured": "Internal ops code 5120101"
      }
    }
  },
  "Risk": {
    "PaymentContextCode": "EcommerceGoods",
    "MerchantCategoryCode": "5967",
    "MerchantCustomerIdentification": "053598653254",
    "DeliveryAddress": {
      "AddressLine": [
        "Flat 7",
        "Acacia Lodge"
      ],
      "StreetName": "Acacia Avenue",
      "BuildingNumber": "27",
      "PostCode": "GU31 2ZZ",
      "TownName": "Sparsholt",
      "CountySubDivision": [
        "Wessex"
      ],
      "Country": "UK"
    }
  }
}

HTTP/1.1 201 Created
x-fapi-interaction-id: 93bac548-d2de-4546-b106-880a5018460d
Content-Type: application/json
 
{
  "Data": {
    "PaymentId": "58923",
    "Status": "AcceptedTechnicalValidation",
    "CreationDateTime": "2017-06-05T15:15:13+00:00",
    "Initiation": {
      "InstructionIdentification": "ACME412",
      "EndToEndIdentification": "FRESCO.21302.GFX.20",
      "InstructedAmount": {
        "Amount": "165.88",
        "Currency": "GBP"
      },
      "CreditorAccount": {
        "SchemeName": "SortCodeAccountNumber",
        "Identification": "08080021325698",
        "Name": "ACME Inc",
        "SecondaryIdentification": "0002"
      },
      "RemittanceInformation": {
        "Reference": "FRESCO-101",
        "Unstructured": "Internal ops code 5120101"
      }
    }
  },
  "Risk": {
    "PaymentContextCode": "EcommerceGoods",
    "MerchantCategoryCode": "5967",
    "MerchantCustomerIdentification": "053598653254",
    "DeliveryAddress": {
      "AddressLine": [
        "Flat 7",
        "Acacia Lodge"
      ],
      "StreetName": "Acacia Avenue",
      "BuildingNumber": "27",
      "PostCode": "GU31 2ZZ",
      "TownName": "Sparsholt",
      "CountySubDivision": [
        "Wessex"
      ],
      "Country": "UK"
    }
  },
  "Links": {
    "Self": "https://api.alphabank.com/open-banking/v1.0/payments/58923"
  },
  "Meta": {}
}

Step 3 - Authorize Consent

1. PISP receives a PaymentId from the ASPSP. The PISP then creates an Authorization request (using a signed JWT Request containing the PaymentID as a claim) for the PSU to consent to the Payment directly with their ASPSP. The request is an OIDC Hybrid flow (requesting for Code and id_token)

Request : OIDC Hybrid Flow

Response : OIDC Hybrid Flow

Sourced from the OB Security Profile Request Object section

Base 64 Encoded Example

GET /authorize?
response_type=code id_token
&client_id=s6BhdRkqt3
&state=af0ifjsldkj
&scope=openid payments
&nonce=n-0S6_WzA2Mj
&redirect_uri=https://api.mytpp.com/cb
&request=CJleHAiOjE0OTUxOTk1ODd.....JjVqsDuushgpwp0E.5leGFtcGxlI
iwianRpIjoiM....JleHAiOjE0.olnx_YKAm2J1rbpOP8wGhi1BDNHJjVqsDuushgpwp0E

Non-Base64 encoded example of the request parameter object

{
    "alg": "",
    "kid": "GxlIiwianVqsDuushgjE0OTUxOTk"
}
.
{
   "iss": "https://api.alphabank.com",
   "aud": "s6BhdRkqt3",
   "response_type": "code id_token",
   "client_id": "s6BhdRkqt3",
   "redirect_uri": "https://api.mytpp.com/cb",
   "scope": "openid payments accounts",
   "state": "af0ifjsldkj",
   "nonce": "n-0S6_WzA2Mj",
   "max_age": 86400,
   "claims":
    {
     "userinfo":
      {
       "openbanking_intent_id": {"value": "urn:alphabank:intent:58923", "essential": true}
      },
     "id_token":
      {
       "openbanking_intent_id": {"value": "urn:alphabank:intent:58923", "essential": true},
       "acr": {"essential": true,
				"values": ["urn:openbanking:psd2:sca",
                     "urn:openbanking:psd2:ca"]}}}
      }
    }
}
.
<<signature>>

After the PSU has consented directly with the ASPSP via their web application (and confirmed the Debtor account) the ASPSP validates the Authorization request and generates an Auth Code and ID Token

HTTP/1.1 302 Found
  Location: https://api.mytpp.com/cb#
    code=SplxlOBeZQQYbYS6WxSbIA
    &id_token=eyJ0 ... NiJ9.eyJ1c ... I6IjIifX0.DeWt4Qu ... ZXso
    &state=af0ifjsldkj

2. The PSU is then redirected to the PISP. The PISP will now possess the Authorization Code and ID Token from the ASPSP. Note at this point, there is no Access Token. The PISP will now introspect the ID Token and use it as a detached signature to check:

The hash of the Authorization Code to prove it hasn't been tampered with during redirect (comparing the hash value against the c_hash attribute in ID Token)
The hash of the State to prove it hasn't been tampered with during redirect (comparing the state hash value against the s_hash attribute in the ID Token)

Example: ID Token

Sourced from the OB Security Profile Request Object section

 {
  "alg": "RS256",
  "kid": "12345",
  "typ": "JWT"
}
. 
{
   "iss": "https://api.alphabank.com",
   "iat": 1234569795,
   "sub": "urn:alphabank:payment:58923",
   "acr": "urn:openbanking:psd2:ca",
   "openbanking_intent_id": "urn:alphabank:payment:58923",
   "aud": "s6BhdRkqt3",
   "nonce": "n-0S6_WzA2Mj",
   "exp": 1311281970,
   "s_hash": "76sa5dd",
   "c_hash": "asd097d"
  }
.
{
<<signature>> 
}

3. Once the state and code validations have been confirmed as successful by use of the ID token, the PISP will proceed to obtain an Access Token from the ASPSP using the Authorization Code they now possess. The PISP will present its Authorization Code together with the private_key_jwt. The Access Token is required by the PISP in order to submit the Payment on behalf of the PSU. The payments scope should already be associated with the Authorization Code generated in the previous step.

Request : Access Token Request using Authorization Code and private_key_jwt

Response : Access Token

POST /as/token.oauth2 HTTP/1.1
Host: https://authn.alphabank.com
Content-Type: application/x-www-form-urlencoded
Accept: application/json
grant_type=authorization_code
&code=SplxlOBeZQQYbYS6WxSbIA
&redirect_uri=https://api.mytpp.com/cb
&client_assertion_type=
    urn%3Aietf%3Aparams%3Aoauth%3Aclient-assertion-type%3Ajwt-bearer
&client_assertion=eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRw
czovL2p3dC1pZHAuZXhhbXBsZS5jb20iLCJzdWIiOiJtYWlsdG86bWlrZUBleGFtcGxlLmN
vbSIsIm5iZiI6MTQ5OTE4MzYwMSwiZXhwIjoxNDk5MTg3MjAxLCJpYXQiOjE0OTkxODM2MD
EsImp0aSI6ImlkMTIzNDU2IiwidHlwIjoiaHR0cHM6Ly9leGFtcGxlLmNvbS9yZWdpc3Rlc
iJ9.SAxPMaJK_wYl_W2idTQASjiEZ4UoI7-P2SbmnHKr6LvP8ZJZX6JlnpK_xClJswAni1T
p1UnHJslc08JrexctaeEIBrqwHG18iBcWKjhHK2Tv5m4nbTsSi1MFQOlMUTRFq3_LQiHqV2
M8Hf1v9q9YaQqxDa4MK0asDUtE_zYMHz8kKDb-jj-Vh4mVDeM4_FPiffd2C5ckjkrZBNOK0
01Xktm7xTqX6fk56KTrejeA4x6D_1ygJcGfjZCv6Knki7Jl-6MfwUKb9ZoZ9LiwHf5lLXPuy
_QrOyM0pONWKj9K4Mj7I4GPGvzyVqpaZUgjcOaZY_rlu_p9tnSlE781dDLuw

Non-Base64 JWT client_assertion

{
  "alg": "RS256",
  "kid": "12345",
  "typ": "JWT"
}
.
{
  "iss": "s6BhdRkqt3",
  "sub": "s6BhdRkqt3",
  "exp": 1499187201,
  "iat": 1499183601,
  "jti": "id123456",
  "aud": "https://authn.alphabank.com/as/token.oauth2"
}
.
<<signature>>

  HTTP/1.1 200 OK
  Content-Type: application/json
  Cache-Control: no-store
  Pragma: no-cache

  {
   "access_token": "SlAV32hkKG",
   "token_type": "Bearer",
   "expires_in": 3600
  }

Step 4 - Create Payment-Submission

1. The PISP has an Access Token which can be used to Create a Payment-Submission (Step 4). The PISP must obtain the PaymentId (Intent-ID) so that the Payment request is associated with the correct PaymentId. This can be sourced from either:

The PaymentId claim from the signed ID Token (default). The PISP will need to decode the ID Token JWT and locate the claim attribute associated with the PaymentId.
The PaymentId claim from the /userInfo resource endpoint of the ASPSP (optional for ASPSPs to implement) .

The example below provides an illustration of the PISP requesting the /userInfo endpoint of the ASPSP in order to get the PaymentID (returned as openbanking_intent_id)

Request : UserInfo

Response : UserInfo

GET /userinfo HTTP/1.1
  Host: api.alphabank.com
  Authorization: Bearer SlAV32hkKG

  HTTP/1.1 200 OK
  Content-Type: application/json

  {
   "sub": "PSU User Id",
   "openbanking_intent_id": [ "IntentId:1", "IntentId:2" ],
   "name": "Open Banking",
   "given_name": "Open Banking",
   "family_name": "Open Banking",
   "preferred_username": "Open Banking",
   "email": "Open Banking@example.com",
   "picture": "http://example.com/janedoe/me.jpg"
  }

2. The PISP can now invoke the /payment-submissions endpoint to commit the Payment using the Access Token and PaymentId in the payload of the request. This example is sourced from the Payment Initiation API Specification

Request : payment-submissions

Response : payment-submissions

POST /payment-submissions HTTP/1.1
Authorization: Bearer SlAV32hkKG
x-idempotency-key: FRESNO.1317.GFX.22
x-fapi-financial-id: OB/2017/001
x-fapi-customer-last-logged-time: 2017-06-13T11:36:09
x-fapi-customer-ip-address: 104.25.212.99
x-fapi-interaction-id: 93bac548-d2de-4546-b106-880a5018460d
Content-Type: application/json
Accept: application/json
 
{
  "Data": {
    "PaymentId": "58923",
    "Initiation": {
      "InstructionIdentification": "ACME412",
      "EndToEndIdentification": "FRESCO.21302.GFX.20",
      "InstructedAmount": {
        "Amount": "165.88",
        "Currency": "GBP"
      },
      "CreditorAccount": {
        "SchemeName": "SortCodeAccountNumber",
        "Identification": "08080021325698",
        "Name": "ACME Inc",
        "SecondaryIdentification": "0002"
      },
      "RemittanceInformation": {
        "Reference": "FRESCO-101",
        "Unstructured": "Internal ops code 5120101"
      }
    }
  },
  "Risk": {
    "PaymentContextCode": "EcommerceGoods",
    "MerchantCategoryCode": "5967",
    "MerchantCustomerIdentification": "053598653254",
    "DeliveryAddress": {
      "AddressLine": [
        "Flat 7",
        "Acacia Lodge"
      ],
      "StreetName": "Acacia Avenue",
      "BuildingNumber": "27",
      "PostCode": "GU31 2ZZ",
      "TownName": "Sparsholt",
      "CountySubDivision": [
        "Wessex"
      ],
      "Country": "UK"
    }
  }
}

HTTP/1.1 201 Created
x-fapi-interaction-id: 93bac548-d2de-4546-b106-880a5018460d
Content-Type: application/json
 
{
  "Data": {
    "PaymentSubmissionId": "58923-001",
    "PaymentId": "58923",
    "Status": "AcceptedSettlementInProcess",
    "CreationDateTime": "2017-06-05T15:15:22+00:00"
  },
  "Links": {
    "Self": "https://api.alphabank.com/open-banking/v1.0/payment-submissions/58923-001"
  },
  "Meta": {}
}

Step 5 - Get Payment-Submission Status

1. The PISP can query for the status of a Payment-Submission by invoking the /payment-submissions using the known PaymentSubmissionId. This can use an existing access token with payments scope or the PISP can obtain a fresh access token by replaying the client credentials grant request as per Step 2 - Setup Single Payment Initiation.

Request: payment-submissions/{PaymentSubmissionId}

Response: payment-submissions

GET /payment-submissions/58923-001 HTTP/1.1
Authorization: Bearer SlAV32hkKG
x-fapi-financial-id: OB/2017/001
x-fapi-customer-last-logged-time: 2017-06-13T11:36:09
x-fapi-customer-ip-address: 104.25.212.99
x-fapi-interaction-id: 93bac548-d2de-4546-b106-880a5018460d
Accept: application/json

HTTP/1.1 200 OK
x-fapi-interaction-id: 93bac548-d2de-4546-b106-880a5018460d
Content-Type: application/json
 
{
  "Data": {
    "PaymentSubmissionId": "58923-001",
    "PaymentId": "58923",
    "Status": "AcceptedSettlementInProcess",
    "CreationDateTime": "2017-06-05T15:15:22+00:00"
  },
  "Links": {
    "Self": "https://api.alphabank.com/open-banking/v1.0/payment-submissions/58923-001"
  },
  "Meta": {}
}

2. A PISP can also optionally query for the status of a Payment resource by invoking /payments/{PaymentId}. This can use an existing access token with payments scope or the PISP can obtain a fresh access token by replaying the client credentials grant request as per Step 2 - Setup Single Payment Initiation.

Account API Specification

The sequence diagram below highlights the OAuth 2.0 Client Credentials Grant and OIDC Hybrid flow that are used by the Account and Transactions API.

Account and Transactions API with Client Credentials Grant and OIDC Hybrid flow

participant PSU
participant AISP
participant ASPSP Authorisation Server
participant ASPSP Resource Server
autonumber 1
      
PSU -> AISP: Establish TLS 1.2
    
      
note over PSU, ASPSP Resource Server
    Step 1: Request account information
end note
PSU -> AISP: Get account/transaction information
     
note over PSU, ASPSP Resource Server
    Step 2: Setup account request
end note
AISP <-> ASPSP Authorisation Server: Establish TLS 1.2 MA
    
    note left of AISP
        Client Credentials Grant
    end note
    AISP->ASPSP Authorisation Server: POST /token (client authentication credentials, scope:accounts)
    ASPSP Authorisation Server->ASPSP Authorisation Server: Validate client authentication credentials, scope
    ASPSP Authorisation Server->ASPSP Authorisation Server: Validate clientId matches client SSL cert
    ASPSP Authorisation Server -> AISP: HTTP 200 (OK) access-token (scope:accounts)
    
    
AISP <-> ASPSP Resource Server: Establish TLS 1.2 MA
AISP -> ASPSP Resource Server: POST /account-requests (access-token - scope:accounts)
    ASPSP Resource Server->ASPSP Resource Server: Validate access token
    ASPSP Resource Server->ASPSP Resource Server: Validate scope:accounts
    ASPSP Resource Server->ASPSP Resource Server: Validate clientId matches client SSL cert
    ASPSP Resource Server->ASPSP Resource Server: Create new account resource
    ASPSP Resource Server->ASPSP Resource Server: Bind AccountRequestId with ClientId
    
ASPSP Resource Server -> AISP: HTTP 201 (Created), AccountRequestId
    note right of AISP
        Begin OIDC Hybrid Flow.
        See 6.1.  Passing a Request Object by Value
        See 5.5.  Requesting Claims using the "claims" Request Parameter
        The claims parameter must at least request:
             "id_token": {
       "openbanking_intent_id": {"value": AccountRequestId, "essential": true},
       "acr": {"essential": true}
      }
      The response object must be signed using the PISP's private key.
    end note
    AISP->AISP: Persist AccountRequestId
      note right of AISP
        The AISP should store the AccountRequestId in a manner
        that it can be retrieved again later in the flow in Step 4.
             
        This could be stored in the user session (and retrieved using 'state'
        as a key) or the PSU could use some other unique identifier.
             
        This can be re-retrieved in [81] and [96].
             
    end note
    
    AISP->AISP: Create signed request object with requested Claims (AccountRequestId)
        
    
    
    AISP -> PSU: HTTP 302 (Found); Location: /authorize,\nredirect-uri, clientId, state, nonce, scope=openid accounts,\nresponse-type=code id_token,\nrequest=signed JWT request object - AccountRequestId)
    
     
note over PSU, ASPSP Resource Server
Step 3: Authorise consent
end note
PSU -> ASPSP Authorisation Server: HTTP GET /authorize redirect-uri, clientId, state, nonce, scope=openid accounts, response-type=code id_token,\nrequest=signed JWT request object - AccountRequestId
ASPSP Authorisation Server->ASPSP Authorisation Server: Validate clientid, scope
ASPSP Authorisation Server->ASPSP Authorisation Server: Validate redirect-uri for clientId
ASPSP Authorisation Server->ASPSP Authorisation Server: Validate JWT request claim -AccountRequestId
note right of ASPSP Authorisation Server
        Validate the request object by using the PISP's public key.
        PISP certificate will be identified using the kid claim
        in the JOSE header of the request object.
             
        Check that the AccountRequestId belongs to the ClientId that initiated the request.
    end note
    
PSU <-> ASPSP Authorisation Server: Authenticate (Login and Consent Page)
PSU <-> ASPSP Authorisation Server: SCA if required
PSU <-> ASPSP Authorisation Server: Select Accounts
ASPSP Authorisation Server->ASPSP Authorisation Server: Generate authorization-code, id_token
note right of ASPSP Authorisation Server
    id_token claims:{
    c_hash: 123,
    s_hash: 456
    }
    id_token must be signed using the ASPSP's private key.
    The generation of c_hash is documented in OIDC: 3.3.2.11.  ID Token
    The generation of s_hash is in FAPI R/W spec: Section 5.1
    http://openid.net/specs/openid-financial-api-part-2-wd-02.html#introduction
end note
ASPSP Authorisation Server-> ASPSP Authorisation Server: Bind selected Accounts to AccountRequestId
ASPSP Authorisation Server -> PSU: HTTP 302 (Found); Location: redirect-uri (authorization-code, id_token, state)
PSU -> AISP: HTTP GET redirect-uri (authorization-code, id_token, state)
AISP->AISP: Validate signature on id_token
note right of AISP
    Validate the id_token by using the ASPSP's public key.
    ASPSP certificate will be identified using the kid claim
    in the JOSE header of the id_token
end note
AISP->AISP: Validate authorization-code using id_token (c_hash)
AISP->AISP: Validate state using id_token (s_hash)
AISP->AISP: Validate nonce using id_token
note right of AISP:
    Exchange authorization-code for access token.
end note
    
    
    
AISP <-> ASPSP Authorisation Server: Establish TLS 1.2 MA
AISP -> ASPSP Authorisation Server: HTTP POST /token (client authentication credentials,\nauthorization-code, grant_type, redirect_uri)
    ASPSP Authorisation Server->ASPSP Authorisation Server: Validate clientId matches client SSL cert
    ASPSP Authorisation Server->ASPSP Authorisation Server: Validate client authentication credentials,\nauthorization-code
    ASPSP Authorisation Server->ASPSP Authorisation Server: Generate access-token
    ASPSP Authorisation Server->ASPSP Authorisation Server: Bind access-token to AccountRequestId
    note right of ASPSP Authorisation Server
        Implies an association of Accounts to access-token
    end note
    ASPSP Authorisation Server->ASPSP Resource Server: Update account-requests Status to Authorised
    ASPSP Resource Server->ASPSP Authorisation Server:OK
    note right of ASPSP Authorisation Server
        Implementation of how the resource is updated is ASPSP specific (There
        is no standardised API for this)
    end note
alt Access Token
    ASPSP Authorisation Server -> AISP: HTTP 200 (OK) access-token (scope:accounts)
  
else Optional Refresh Token
    ASPSP Authorisation Server->ASPSP Authorisation Server: Generate Refresh Token
    ASPSP Authorisation Server -> AISP: HTTP 200 (OK) access-token, refresh-token (scope:accounts)
  
end
     
      
note over PSU, ASPSP Resource Server
Step 4: Request data
end note
AISP <-> ASPSP Resource Server: Establish TLS 1.2 MA
AISP<->AISP: Retrieve access-token
note left of AISP
    Retrieve the access-token that was issued in Step [42].
    The access-token is  linked with consented Accounts
    from Steps [27] and [39]
end note
  
alt Valid Access Token
    AISP -> ASPSP Resource Server: GET /accounts (access-token - scope:accounts)
    ASPSP Resource Server->ASPSP Resource Server: Validate access-token
    ASPSP Resource Server->ASPSP Resource Server: Validate access-token matches client SSL cert
    ASPSP Resource Server->ASPSP Resource Server: Validate scope:accounts
    ASPSP Resource Server -> AISP: HTTP 200 (OK), List of accounts containing AccountId(s)
    AISP -> ASPSP Resource Server: GET /accounts/{AccountId}/transactions (access-token - scope:accounts)
    ASPSP Resource Server->ASPSP Resource Server: Validate access-token
    ASPSP Resource Server->ASPSP Resource Server: Validate access-token matches client SSL cert
 
    ASPSP Resource Server->ASPSP Resource Server: Validate scope:accounts
    ASPSP Resource Server->ASPSP Resource Server: Validate access-token bound to AccountId
    ASPSP Resource Server -> AISP: HTTP 200 (OK), List of transactions
else Expired Access Token
    AISP->AISP: Retrieve Refresh Token from [44]
    AISP->ASPSP Authorisation Server:HTTP POST /token (client authentication credentials,\ngrant_type=refresh_token,refresh_token=[58],\nscope=openid accounts)
    ASPSP Authorisation Server->ASPSP Authorisation Server: Validate clientId matches client SSL cert
    ASPSP Authorisation Server->ASPSP Authorisation Server: Validate client authentication credentials,\refresh_token
    ASPSP Authorisation Server->ASPSP Authorisation Server: Generate Access Token and Refresh Token
    ASPSP Authorisation Server -> AISP: HTTP 200 (OK) access-token, refresh-token (scope:accounts)
    AISP -> ASPSP Resource Server: GET /accounts (access-token - scope:accounts)
    ASPSP Resource Server->ASPSP Resource Server: Validate access-token
    ASPSP Resource Server->ASPSP Resource Server: Validate access-token matches client SSL cert
    ASPSP Resource Server->ASPSP Resource Server: Validate scope:accounts
    ASPSP Resource Server -> AISP: HTTP 200 (OK), List of accounts containing AccountId(s)
    AISP -> ASPSP Resource Server: GET /accounts/{AccountId}/transactions (access-token - scope:accounts)
    ASPSP Resource Server->ASPSP Resource Server: Validate access-token
    ASPSP Resource Server->ASPSP Resource Server: Validate access-token matches client SSL cert
    ASPSP Resource Server->ASPSP Resource Server: Validate scope:accounts
    ASPSP Resource Server->ASPSP Resource Server: Validate access-token bound to AccountId
    ASPSP Resource Server -> AISP: HTTP 200 (OK), List of transactions
else Account Request - Get Status
AISP <-> ASPSP Authorisation Server: Establish TLS 1.2 MA
    
    note left of AISP
        Client Credentials Grant
    end note
    AISP->ASPSP Authorisation Server: POST /token (client authentication credentials, scope:accounts)
    ASPSP Authorisation Server->ASPSP Authorisation Server: Validate client authentication credentials, scope
    ASPSP Authorisation Server->ASPSP Authorisation Server: Validate clientId matches client SSL cert
    ASPSP Authorisation Server -> AISP: HTTP 200 (OK) access-token (scope:accounts)
    
    
    AISP <-> ASPSP Resource Server: Establish TLS 1.2 MA
    AISP->AISP: Retrieve AccountRequestId from [16]
    AISP -> ASPSP Resource Server: GET /account-requests/{AccountRequestId} (access-token - scope:accounts)
        ASPSP Resource Server->ASPSP Resource Server: Validate access token
        ASPSP Resource Server->ASPSP Resource Server: Validate scope:accounts
        ASPSP Resource Server->ASPSP Resource Server: Validate clientId matches client SSL cert
        ASPSP Resource Server->ASPSP Resource Server: Lookup AccountRequestId resource
     
    ASPSP Resource Server -> AISP: HTTP 200 (OK), AccountRequest Status
 
else Account Request- PSU removes consent at a later point in time with the AISP
PSU -> AISP: Establish TLS 1.2
PSU -> AISP: Remove Consent
 
AISP <-> ASPSP Authorisation Server: Establish TLS 1.2 MA
    
    note left of AISP
        Client Credentials Grant
    end note
    AISP->ASPSP Authorisation Server: POST /token (client authentication credentials, scope:accounts)
    ASPSP Authorisation Server->ASPSP Authorisation Server: Validate client authentication credentials, scope
    ASPSP Authorisation Server->ASPSP Authorisation Server: Validate clientId matches client SSL cert
    ASPSP Authorisation Server -> AISP: HTTP 200 (OK) access-token (scope:accounts)
    
    
    AISP <-> ASPSP Resource Server: Establish TLS 1.2 MA
    AISP->AISP: Retrieve AccountRequestId from [16]
    AISP -> ASPSP Resource Server: DELETE /account-requests/{AccountRequestId} (access-token - scope:accounts)
        ASPSP Resource Server->ASPSP Resource Server: Validate access token
        ASPSP Resource Server->ASPSP Resource Server: Validate scope:accounts
        ASPSP Resource Server->ASPSP Resource Server: Validate clientId matches client SSL cert
        ASPSP Resource Server->ASPSP Resource Server: Delete AccountRequestId resource
     
    ASPSP Resource Server -> AISP: HTTP 204 (No Content)
    AISP->PSU: Consent Removed
end

Client Credentials Grant Type (OAuth 2.0)

Summary

This grant type is used by the AISP in Step 2 to register an intent for the PSU to allow the AISP to retrieve their Account information from an ASPSP.

The AISP initiates an Authorization request using valid Client Credentials Grant type and scope(s)
The ASPSP Authorization Server validates the Client Authentication request from the AISP and generates an Access Token response where the request is valid
The AISP uses the Access Token to create a new Account Request resource against the ASPSP Resource Server
The ASPSP Resource server responds with the AccountRequestId representing the resource it has created.

OIDC Hybrid Flow

Summary

This is initiated at the end of Step 2 by the AISP after the AccountRequestId is generated by the ASPSP and returned to the AISP.
This is used in a redirect across the PSU and ASPSP in Step 3 in order for the PSU to authorize consent with the ASPSP - for the AISP to proceed with the requesting Account information.
This is used across the AISP and ASPSP in Step 4 by swapping the Authorization Code for an Access Token in order to retrieve PSU Account information.

Non-Normative HTTP Request and Response Examples

Step 1 - Request Account Information

There are no Requests and Responses against the Payments API in this Step for the PSU, PISP and ASPSP.

Step 2 - Setup Account Request

1. AISP obtains an Access Token using a Client Credentials Grant Type. The scope accounts must be used. When an Access Token expires, the AISP will need to re-request for another Access Token using the same request below.

Request : Client Credentials using private_key_jwt

Response : Client Credentials

POST  /as/token.oauth2 HTTP/1.1
Host: https://authn.alphabank.com
Content-Type: application/x-www-form-urlencoded
Accept: application/json
grant_type=client_credentials
&scope=accounts
&client-assertion-type%3Ajwt-bearer
&client_assertion=eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRw
czovL2p3dC1pZHAuZXhhbXBsZS5jb20iLCJzdWIiOiJtYWlsdG86bWlrZUBleGFtcGxlLmN
vbSIsIm5iZiI6MTQ5OTE4MzYwMSwiZXhwIjoxNDk5MTg3MjAxLCJpYXQiOjE0OTkxODM2MD
EsImp0aSI6ImlkMTIzNDU2IiwidHlwIjoiaHR0cHM6Ly9leGFtcGxlLmNvbS9yZWdpc3Rlc
iJ9.SAxPMaJK_wYl_W2idTQASjiEZ4UoI7-P2SbmnHKr6LvP8ZJZX6JlnpK_xClJswAni1T
p1UnHJslc08JrexctaeEIBrqwHG18iBcWKjhHK2Tv5m4nbTsSi1MFQOlMUTRFq3_LQiHqV2
M8Hf1v9q9YaQqxDa4MK0asDUtE_zYMHz8kKDb-jj-Vh4mVDeM4_FPiffd2C5ckjkrZBNOK0
01Xktm7xTqX6fk56KTrejeA4x6D_1ygJcGfjZCv6Knki7Jl-6MfwUKb9ZoZ9LiwHf5lLXPuy
_QrOyM0pONWKj9K4Mj7I4GPGvzyVqpaZUgjcOaZY_rlu_p9tnSlE781dDLuw

Non-Base64 JWT client_assertion

{
  "alg": "RS256",
  "typ": "JWT",
  "kid": "1234adsf"
}
.
{
  "iss": "s6BhdRkqt3",
  "sub": "s6BhdRkqt3",
  "exp": 1499187201,
  "iat": 1499183601,
  "jti": "id123456",
  "aud": "https://authn.alphabank.com/as/token.oauth2"
}
.
<<signature>>

Content-Length: 1103
Content-Type: application/json
Date: Mon, 26 Jun 2017 15:18:28 GMT
{
    "access_token": "2YotnFZFEjr1zCsicMWpAA",
    "expires_in": 3600,
    "token_type": "bearer",
	"scope":"accounts"
}

2. AISP uses the Access Token (with accounts scope) from the ASPSP to invoke the Accounts API. This example is sourced directly from the Account and Transactions API Specification

Request: Accounts API

Response: Accounts API

POST /account-requests HTTP/1.1
Authorization: Bearer 2YotnFZFEjr1zCsicMWpAA
x-fapi-financial-id: OB/2017/001
x-fapi-customer-last-logged-time: 2017-06-13T11:36:09
x-fapi-customer-ip-address: 104.25.212.99
x-fapi-interaction-id: 93bac548-d2de-4546-b106-880a5018460d
Content-Type: application/json
Accept: application/json

{
  "Data": {
    "Permissions": [
      "ReadAccountsDetail",
      "ReadBalances",
      "ReadBeneficiariesDetail",
      "ReadDirectDebits",
      "ReadProducts",
      "ReadStandingOrdersDetail",
      "ReadTransactionsCredits",
      "ReadTransactionsDebits",
      "ReadTransactionsDetail"
    ],
    "ExpirationDateTime": "2017-05-02T00:00:00+00:00",
    "TransactionFromDateTime": "2017-05-03T00:00:00+00:00",
    "TransactionToDateTime": "2017-12-03T00:00:00+00:00"
  },
  "Risk": {}
}

HTTP/1.1 201 Created
x-fapi-interaction-id: 93bac548-d2de-4546-b106-880a5018460d
Content-Type: application/json
 
{
  "Data": {
    "AccountRequestId": "88379",
    "Status": "AwaitingAuthorisation",
    "CreationDateTime": "2017-05-02T00:00:00+00:00",
    "Permissions": [
      "ReadAccountsDetail",
      "ReadBalances",
      "ReadBeneficiariesDetail",
      "ReadDirectDebits",
      "ReadProducts",
      "ReadStandingOrdersDetail",
      "ReadTransactionsCredits",
      "ReadTransactionsDebits",
      "ReadTransactionsDetail"
    ],
    "ExpirationDateTime": "2017-08-02T00:00:00+00:00",
    "TransactionFromDateTime": "2017-05-03T00:00:00+00:00",
    "TransactionToDateTime": "2017-12-03T00:00:00+00:00"
  },
  "Risk": {},
  "Links": {
    "Self": "/account-requests/88379"
  },
  "Meta": {
    "TotalPages": 1
  }
}

Step 3 - Authorize Consent

1. AISP receives a AccountRequestId from the ASPSP. The AISP then creates an Authorization request (using a signed JWT Request containing the AccountRequestId as a claim) for the PSU to consent to the Account request directly with their ASPSP. The request is an OIDC Hybrid flow (requesting for Code and id_token)

Request : OIDC Hybrid Flow

Response : OIDC Hybrid Flow

Sourced from the OB Security Profile Request Object section

Base 64 Encoded Example

GET /authorize?
response_type=code id_token
&client_id=s6BhdRkqt3
&state=af0ifjsldkj
&scope=openid accounts
&nonce=n-0S6_WzA2Mj
&redirect_uri=https://api.mytpp.com/cb
&request=CJleHAiOjE0OTUxOTk1ODd.....JjVqsDuushgpwp0E.5leGFtcGxlI
iwianRpIjoiM....JleHAiOjE0.olnx_YKAm2J1rbpOP8wGhi1BDNHJjVqsDuushgpwp0E

Non-Base64 encoded example of the request parameter object

{
    "alg": "RS256",
    "kid": "GxlIiwianVqsDuushgjE0OTUxOTk"
}
.
{
   "iss": "https://api.alphabank.com",
   "aud": "s6BhdRkqt3",
   "response_type": "code id_token",
   "client_id": "s6BhdRkqt3",
   "redirect_uri": "https://api.mytpp.com/cb",
   "scope": "openid payments accounts",
   "state": "af0ifjsldkj",
   "nonce": "n-0S6_WzA2Mj",
   "max_age": 86400,
   "claims":
    {
     "userinfo":
      {
       "openbanking_intent_id": {"value": "urn:alphabank:intent:88379", "essential": true}
      },
     "id_token":
      {
       "openbanking_intent_id": {"value": "urn:alphabank:intent:88379", "essential": true},
       "acr": {"essential": true,
				"values": ["urn:openbanking:psd2:sca",
                     "urn:openbanking:psd2:ca"]}}
      }
    }
}
.
<<signature>>

After the PSU has consented directly with the ASPSP via their web application (and confirmed Account access) the ASPSP validates the Authorization request and generates an Auth Code and ID Token

HTTP/1.1 302 Found
  Location: https://api.mytpp.com/cb#
    code=SplxlOBeZQQYbYS6WxSbIA
    &id_token=eyJ0 ... NiJ9.eyJ1c ... I6IjIifX0.DeWt4Qu ... ZXso
    &state=af0ifjsldkj

2. The PSU is then redirected to the AISP. The AISP will now possess the Authorization Code and ID Token from the ASPSP. Note at this point, there is no Access Token. The AISP will now introspect the ID Token and use it as a detached signature to check:

The hash of the Authorization Code to prove it hasn't been tampered with during redirect (comparing the hash value against the c_hash attribute in ID Token)
The hash of the State to prove it hasn't been tampered with during redirect (comparing the state hash value against the s_hash attribute in the ID Token)

Example: ID Token

Sourced from the OB Security Profile Request Object section

{
   "alg": "RS256",
  "kid": "GxlIiwianVqsDuushgjE0OTUxOTk"
} 
.
{
   "iss": "https://api.alphabank.com",
   "iat": 1234569795,
   "sub": "urn:alphabank:accountRequestId:88379",
   "acr": "urn:openbanking:psd2:ca",
   "openbanking_intent_id": "urn:alphabank:accountRequestId:88379",
   "aud": "s6BhdRkqt3",
   "nonce": "n-0S6_WzA2Mj",
   "exp": 1311281970,
   "s_hash": "76sa5dd",
   "c_hash": "asd097d"
  }

3. Once the state and code validations have been confirmed as successful by use of the ID token, the AISP will proceed to obtain an Access Token from the ASPSP using the Authorization Code they now possess. The AISP will present its Authorization Code together with the private_key_jwt. The Access Token is required by the AISP in order to access PSU Account information. The accounts scope should already be associated with the Authorization Code generated in the previous step.

Request : Access Token request using Authorization Code and private_key_jwt

Response : Access Token (with Optional Refresh Token)

POST  /as/token.oauth2 HTTP/1.1
Host: https://authn.alphabank.com
Content-Type: application/x-www-form-urlencoded
Accept: application/json
grant_type=authorization_code
&redirect_uri=https://api.mytpp.com/cb
&code=SplxlOBeZQQYbYS6WxSbIA
&client-assertion-type%3Ajwt-bearer
&client_assertion=eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRw
czovL2p3dC1pZHAuZXhhbXBsZS5jb20iLCJzdWIiOiJtYWlsdG86bWlrZUBleGFtcGxlLmN
vbSIsIm5iZiI6MTQ5OTE4MzYwMSwiZXhwIjoxNDk5MTg3MjAxLCJpYXQiOjE0OTkxODM2MD
EsImp0aSI6ImlkMTIzNDU2IiwidHlwIjoiaHR0cHM6Ly9leGFtcGxlLmNvbS9yZWdpc3Rlc
iJ9.SAxPMaJK_wYl_W2idTQASjiEZ4UoI7-P2SbmnHKr6LvP8ZJZX6JlnpK_xClJswAni1T
p1UnHJslc08JrexctaeEIBrqwHG18iBcWKjhHK2Tv5m4nbTsSi1MFQOlMUTRFq3_LQiHqV2
M8Hf1v9q9YaQqxDa4MK0asDUtE_zYMHz8kKDb-jj-Vh4mVDeM4_FPiffd2C5ckjkrZBNOK0
01Xktm7xTqX6fk56KTrejeA4x6D_1ygJcGfjZCv6Knki7Jl-6MfwUKb9ZoZ9LiwHf5lLXPuy
_QrOyM0pONWKj9K4Mj7I4GPGvzyVqpaZUgjcOaZY_rlu_p9tnSlE781dDLuw

Non-Base64 JWT client_assertion

{
  "alg": "RS256",
  "kid": "12345",
  "typ": "JWT"
}
.
{
  "iss": "s6BhdRkqt3",
  "sub": "s6BhdRkqt3",
  "exp": 1499187201,
  "iat": 1499183601,
  "jti": "id123456",
  "aud": "https://authn.alphabank.com/as/token.oauth2"
}
.
<<signature>>

HTTP/1.1 200 OK
Content-Type: application/json
Cache-Control: no-store
Pragma: no-cache
 
{
 "access_token": "SlAV32hkKG",
 "token_type": "Bearer",
 "expires_in": 3600,
 "refresh_token": "1Sm4HAl33z4"
}

Step 4 - Request Account Data

1. The AISP can use the Access Token to retrieve Accounts (bulk or specific). The following examples are from the Account and Transaction API Specification

Where the initial Access Token expires, the AISP can use the Refresh token in order to obtain a fresh Access Token.

Request : Accounts API	Response: Accounts API
Example request against the bulk Accounts resource GET /accounts HTTP/1.1 Authorization: Bearer SlAV32hkKG x-fapi-financial-id: OB/2017/001 x-fapi-customer-last-logged-time: 2017-06-13T11:36:09 x-fapi-customer-ip-address: 104.25.212.99 x-fapi-interaction-id: 93bac548-d2de-4546-b106-880a5018460d Accept: application/json	HTTP/1.1 200 OK x-fapi-interaction-id: 93bac548-d2de-4546-b106-880a5018460d Content-Type: application/json { "Data": { "Account": [ { "AccountId": "22289", "Currency": "GBP", "Nickname": "Bills", "Account": { "SchemeName": "SortCodeAccountNumber", "Identification": "80200110203345", "Name": "Mr Kevin", "SecondaryIdentification": "00021" } }, { "AccountId": "31820", "Currency": "GBP", "Nickname": "Household", "Account": { "SchemeName": "SortCodeAccountNumber", "Identification": "80200110203348", "Name": "Mr Kevin" } } ] }, "Links": { "Self": "/accounts/" }, "Meta": { "TotalPages": 1 } }
Example request for a specific Account Id GET /accounts/22289 HTTP/1.1 Authorization: Bearer SlAV32hkKG x-fapi-financial-id: OB/2017/001 x-fapi-customer-last-logged-time: 2017-06-13T11:36:09 x-fapi-customer-ip-address: 104.25.212.99 x-fapi-interaction-id: 93bac548-d2de-4546-b106-880a5018460d Accept: application/json	HTTP/1.1 200 OK x-fapi-interaction-id: 93bac548-d2de-4546-b106-880a5018460d Content-Type: application/json { "Data": { "Account": [ { "AccountId": "22289", "Currency": "GBP", "Nickname": "Bills", "Account": { "SchemeName": "SortCodeAccountNumber", "Identification": "80200110203345", "Name": "Mr Kevin", "SecondaryIdentification": "00021" } } ] }, "Links": { "Self": "/accounts/22289" }, "Meta": { "TotalPages": 1 } }
Request: Refresh Token request using private_key_jwt	Response: Refresh Token
POST /as/token.oauth2 HTTP/1.1 Host: https://authn.alphabank.com Content-Type: application/x-www-form-urlencoded Accept: application/json grant_type=refresh_token &refresh_token=1Sm4HAl33z4 &scope=openid accounts &client-assertion-type%3Ajwt-bearer &client_assertion=eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRw czovL2p3dC1pZHAuZXhhbXBsZS5jb20iLCJzdWIiOiJtYWlsdG86bWlrZUBleGFtcGxlLmN vbSIsIm5iZiI6MTQ5OTE4MzYwMSwiZXhwIjoxNDk5MTg3MjAxLCJpYXQiOjE0OTkxODM2MD EsImp0aSI6ImlkMTIzNDU2IiwidHlwIjoiaHR0cHM6Ly9leGFtcGxlLmNvbS9yZWdpc3Rlc iJ9.SAxPMaJK_wYl_W2idTQASjiEZ4UoI7-P2SbmnHKr6LvP8ZJZX6JlnpK_xClJswAni1T p1UnHJslc08JrexctaeEIBrqwHG18iBcWKjhHK2Tv5m4nbTsSi1MFQOlMUTRFq3_LQiHqV2 M8Hf1v9q9YaQqxDa4MK0asDUtE_zYMHz8kKDb-jj-Vh4mVDeM4_FPiffd2C5ckjkrZBNOK0 01Xktm7xTqX6fk56KTrejeA4x6D_1ygJcGfjZCv6Knki7Jl-6MfwUKb9ZoZ9LiwHf5lLXPuy _QrOyM0pONWKj9K4Mj7I4GPGvzyVqpaZUgjcOaZY_rlu_p9tnSlE781dDLuw	A new Access Token and Refresh Token will be returned to the AISP for them to query /accounts resources HTTP/1.1 200 OK Content-Type: application/json Cache-Control: no-store Pragma: no-cache { "access_token": "TYstftas123j", "token_type": "Bearer", "expires_in": 3600, "refresh_token": "XUUGas123ed" }

Edge Cases

This section provides further information on potential edge cases that may arise via the implementation of Accounts and Payments API Specifications.

PSU Consent Authorization Interrupt with ASPSP

API

Scenario

Workflow Step

Impact

Solution Options

Payments

Due to an interruption, the PSU does not complete the Authorization of the Payment with the ASPSP when redirected by the PISP (after creating a PaymentId)

Step 3: Authorize Consent

Payment Status remains as Pending or AcceptedTechnicalValidation

The PISP may choose to implement a separate follow up process which reminds the PSU to complete their Authorization consent steps with the ASPSP. This would imply re-using the PaymentId that has a status of Pending or AcceptedTechnicalValidation and re-issuing another Hybrid Flow request to the ASPSP. The implementation of how the follow up process is initiated is in the competitive space for the PISPs to decide.

Accounts

Due to an interruption, the PSU does not complete the Authorization of the Accounts request with the ASPSP when redirected by the AISP (after creating an AccountRequestId)

Step 3: Authorize Consent

Account Status remains as AwaitingAuthorisation

The AISP may choose to implement a separate follow up process which reminds the PSU to complete their Authorization consent steps with the ASPSP. This would imply re-using the AccountRequestId that has a status of AwaitingAuthorisation and re-issuing another Hybrid Flow request to the ASPSP. The implementation of how the follow up process is initiated is in the competitive space for the AISPs to decide.

Open Banking Security Profile - Implementer's Draft v1.1.2

Version Control

UK Open Banking OIDC Security Profile

Security Architecture

OAuth 2.0, OIDC and FAPI

Consuming PSU owned Resources from an ASPSP

Overview

Hybrid Flow Request with Intent Id

Hybrid Grant Parameters

Minimum Conformance

Overview

Example for minimum conformance

HTTP Request

Request JWS (Without Base64 encoding)

id_token returned - Sub being populated with an EphemeralId of the IntentId - Non Normative

JSON Security Suite Information v1.0

General Guidance for JWT Best Practice: To Be Followed Where Appropriate

JWKS Endpoints

General outline for creating a JWS

Step 1: Select the certificate and private key that will be used for signing the JWS

Step 2: Form the JOSE Header

Step 3: Form the payload to be signed

Step 4: Sign and encode the payload

Step 5: Assemble the JWS

Implementation Guide

Overview

Specified Behaviour

Client Types

Grant Types

OIDC Hybrid Flow (response_type=code id_token)

Client Credentials Grant Type using multiple scopes (scope=accounts payments)

Access Tokens

Refresh Tokens

ID Tokens

Authorization Codes

Un-Specified Behaviour

Client Types

Grant Types

OIDC Hybrid Flow (response_type=code id_token token or response_type=code token)

OIDC Implicit Flow (response_type=id_token token or response_type=id_token)

The Implicit Flow does not authenticate the Client that is invoking the request. This is not illustrated in the Payments and Accounts API Specifications.

Client Credentials Grant Type(scope=openid email profile address phone)

Validity Lengths (Authorization Code, Access Token, ID Token, Refresh Token)

Authorization Code

ID Token

Access Token

Refresh Token

Success Flows

Payment API Specification

Client Credentials Grant Type (OAuth 2.0)

Summary

OIDC Hybrid Flow

Summary

Non-Normative HTTP Request and Response Examples

Step 1 - Request Payment Initiation

Step 2 - Setup Single Payment Initiation

Step 3 - Authorize Consent

Step 4 - Create Payment-Submission

Step 5 - Get Payment-Submission Status

Account API Specification

Client Credentials Grant Type (OAuth 2.0)

Summary

OIDC Hybrid Flow

Summary

Non-Normative HTTP Request and Response Examples

Step 1 - Request Account Information

Step 2 - Setup Account Request

Step 3 - Authorize Consent

Step 4 - Request Account Data

Edge Cases

PSU Consent Authorization Interrupt with ASPSP