Revocation

Full Title or Meme

The problem of revoking a grant previously issued by an Identifier or Attribute Provider (IAP) on behalf of a Subject which is a requirement of several privacy regulations.

Context

The collection of User Private Information by a Data Controller now necessitates the ability Authenticate the User under a wide range of challenges, like:

1. Simplest of all the User needs to Authenticate from time to time and on a variety of devices under less than ideal conditions where passwords are mistyped and Alternate Authentication factors are lost or fail.

Problems

• As a general rule any certificate that is issued to any Subject cannot be guaranteed of Revocation because it is not possible to know where that certificate has been used.
• Once a Bearer Token has been issued to a Relying Party by a Identifier or Attribute Provider there is no practical way to issue a Revocation that will guarantee success.

Solutions

• The two canonical ways to revoke any grant (or certificate) is to require that the validity be checked online (OCSP) or to distribute a list of revoke certificates(CRL).
• Many mitigations to the Revocation problem exists, for example giving certificates a very short life time.
• Issue a Refresh Token that can be used by the Relying Party to acquire a fresh access token with a short life time on demand. The IAP would then handle any Revocation for the user which would have no effect during that short life time.
• Require the Authorization endpoint to verify liveness of the token before it authorizes actual access to the Resource.