Initiator Responder ---------------------------------------------------------------- HDR, SK {IDi, [CERTREQ,] [IDr,] SAi2, TSi, TSr} --> <-- HDR, SK {IDr, [CERT,] AUTH, EAP} HDR, SK {EAP} --> <-- HDR, SK {EAP (success)} HDR, SK {AUTH, N(PPK_IDENTITY, PPK_ID) [, N(NO_PPK_AUTH)]} --> <-- HDR, SK {AUTH, SAr2, TSi, TSr [, N(PPK_IDENTITY)]}