Universally Composable Security with Global Setup

Abstract. Cryptographic protocols are often designed and analyzed under some trusted set-up assumptions, namely in settings where the participants have access to global information that is trusted to have some basic security properties. However, current modeling of security in the presence of such set-up falls short of providing the expected security guarantees. A quintessential example of this phenomenon is the deniability concern: there exist natural protocols that meet the strongest known composable security notions, and are still vulnerable to bad interactions with rogue protocols that use the same set-up. We extend the notion of universally composable (UC) security in a way that re-establishes its original intuitive guarantee even for protocols that use globally available set-up. The new formulation prevents bad interactions even with adaptively chosen protocols that use the same set-up. In particular, it guarantees deniability. While for protocols that use no setup the proposed r...

• Type: Conference
• Year: 2007
• Where: TCC
• Authors: Ran Canetti, Yevgeniy Dodis, Rafael Pass, Shabsi Walfish
• Keywords: Cryptographic Protocols, Cryptography, Security, Set-up Assumptions, TCC 2007