LAUSR

Dear editor, One-round key exchange (ORKE) represents a special class of two-message key exchange. It enables two parties to establish a shared session key within only one communication round. The first merit of ORKE is its communication efficiency, particularly because two parties are able to simultaneously run the protocol instance. Therefore, the messages of two session participants (in an ORKE protocol) are completely independent. This property of ORKE could dramatically reduce communication latency. Another advantage of ORKE is its strong security. We stress that the recently proposed ORKE protocols have been shown, without exception, to provide security in very strong security models for authenticated key exchange (AKE). A prominent example of the strong AKE model is the g-eCK-PFS model defined by Yang and Zhang [1], which is extended from the two party eCK-PFS model [2]. It is, surprisingly, the g-eCK-PFS model that can be used to provide security arguments for either two party or multiparty one-round key exchange (MORKE). The g-eCK-PFS model formulates almost all other desirable security properties for AKE, such as perfect forward secrecy, resilience to key compromise impersonation (KCI) attacks, resilience to chosen public key attacks, and resilience to exposure attacks on long-term or ephemeral secret keys.