Paper 2011/050

Authenticated Key Exchange with Synchronized State

Zheng Yang

Abstract

We study the problem on how to either prevent identity impersonation (IDI) attacks or limit its consequences by on-line detecting previously unidentified IDI attacks, where IDI attacks are normally caused by the leakage of identity related long-term key. Such problem has, up until now, lacked a provably good solution. We deal with this problem through the scenario on authenticated key exchange with synchronized state (AKESS). This work provides a security model for AKESS protocols, in which we particularly formalize the security of the synchronized state. We propose a two party execution state synchronization framework for symmetric case, based on which we propose a generic compiler for AKESS protocols. Our goal is to compile any existing passively secure key exchange (KE) protocol to AKESS protocol using synchronized state, without any modification on those KE protocols. The proposal is probably secure in the standard model under standard assumptions.