Specifies the method used to authenticate the client application to the authorization server (VCS). The only supported value is "urn:ietf:params:oauth:client-assertion-type:jwt-client-attestation". It indicates that the client must authenticate using OAuth 2.0 Attestation-Based Client Authentication method.
client_assertionstring
The value MUST contain two JWTs, separated by a "~" character. The first JWT is the client attestation JWT, the second is the client attestation PoP JWT.
REQUIRED when authorization_details parameter is used to request issuance of a certain Credential type as defined in Section 5.1.1. It MUST NOT be used otherwise. It is an array of objects, as defined in Section 7 of [RFC9396].