A user logs into domain A using a PKI certificate on a smartcard protected by an 8 digit PIN. The
credential is cached by the authenticating server in domain A. Later, the user attempts to access a
resource in domain B. This initiates a request to the original authenticating server to somehow
attest to the resource server in the second domain that the user is in fact who they claim to be.
Which of the following is being described?

A.
Authentication

B.
Authorization

C.
SAML

D.
Kerberos