fast-reauth.dita

       Peer                                             Authenticator
	  |							  |
          |                               EAP‐Request/Identity    |
          +<------------------------------------------------------+
          |                                                       |
          | EAP‐Response/Identity                                 :
          | (Includes a fast re‐authentication identity)          |
          +------------------------------------------------------>+
          |                                                       |
          |                          +----------------------------+---+
          |                          | Server recognizes the identity |
          |                          | and agrees to use fast         |
          |                          | re‐authentication              |
          |                          +----------------------------+---+
          |                                                       |
          |  EAP‐Request/SIM/Re‐authentication                    |
          |  (AT_IV, AT_ENCR_DATA, *AT_COUNTER,                   |
          |   *AT_NONCE_S, *AT_NEXT_REAUTH_ID, AT_MAC)            |
          |<------------------------------------------------------+
          |                                                       |
     +----+------------------------------------------+            |
     | Peer verifies AT_MAC and the freshness of     |            |
     | the counter. Peer MAY store the new fast re‐  |            |
     | authentication identity for next re‐auth.     |            |
     +----+------------------------------------------+            |
          |                                                       |
          | EAP-Response/SIM/Re‐authentication                    |
          | (AT_IV, AT_ENCR_DATA, *AT_COUNTER with same value,    |
          |  AT_MAC)                                              |
          +------------------------------------------------------>|
          |                          +----------------------------+---+
          |                          | Server verifies AT_MAC and     |
          |                          | the counter                    |
          |                          +----------------------------+---+
          |                                                       |
          |                                          EAP‐Success  |
          |<------------------------------------------------------+