RFC 7029 Mutual Crypto Binding

As the Extensible Authentication Protocol (EAP) evolves, EAP peers rely increasingly on information received from the EAP server. EAP extensions such as channel binding or network posture information are often carried in tunnel methods; peers are likely to rely on this information. Cryptographic binding is a facility described in RFC 3748 that protects tunnel methods against man-in-the-middle attacks. However, cryptographic binding focuses on protecting the server rather than the peer. This memo explores attacks possible when the peer is not protected from man-in-the-middle attacks and recommends cryptographic binding based on an Extended Master Session Key, a new form of cryptographic binding that protects both peer and server along with other mitigations.