SECURE AUTHENTICATED CHANNEL

A protocol (i.e. method) and corresponding apparatuses for calculating a session key. Two peers with knowledge of a common Diffie-Hellman permanent key, Kperm, and the identity and public key of the other peer. A first peer chooses a first ephemeral private key x and calculates the first corresponding ephemeral public key gx, which is sent to the second peer. The second peer calculates a second ephemeral public key gy in the same manner, and an ephemeral shared key Keph, hashes gy, Keph, Kperm, and its identity, and sends gy and the hash to the first peer. The first peer calculates Keph, verifies the hash, and hashes gx, Keph, Kperm, and its identity, and sends it to the second peer that verifies this hash. Thereafter, both peers obtain a session key by hashing Keph. The apparatuses may then use the session key to establish a secure authenticated channel (SAC).