Computationally-Fair group and identity-based key-exchange

摘要: In this work, we re-examine some fundamental group key-exchange and identity-based protocols, specifically the Burmester-Desmedet protocol [7] (referred to as BD-protocol) Chen-Kudla [9] CK-protocol). We identify new attacks on these showing in particular that protocols are not computationally fair. Specifically, with our attacks, an adversary can do following damages: It compute session-key output much lesser computational complexity than of victim honest player, maliciously nullify contributions from players. It set be pre-determined value, which efficiently publicly computed without knowing any secrecy supposed held by attacker. We remark beyond traditional security models for key-exchange, yet bring perspectives literature key-exchange. then present fixing approaches, prove fixed