Used to provide proof of authentication.
This property is determined by the Access Control Server (ACS), and is filled after the call to SendAuthRequest (for a frictionless flow), or when the Results Request Message (RReq) is parsed using CheckResponse (for a challenge flow).
This property will be valid if the TransactionStatus is "Y" or "A". The value may be used to provide proof of authentication.
This property is read-only.