Universally Composable Password-Based Key Exchange

Abstract. We propose and realize a definition of security for passwordbased key exchange within the framework of universally composable (UC) security, thus providing security guarantees under arbitrary composition with other protocols. In addition, our definition captures some aspects of the problem that were not adequately addressed by most prior notions. For instance, it does not assume any underlying probability distribution on passwords, nor does it assume independence between passwords chosen by different parties. We also formulate a definition of password-based secure channels, and show that such a definition is achievable given password-based key exchange. Our protocol realizing the new definition of password-based key exchange is in the common reference string model and relies on standard numbertheoretic assumptions. The components of our protocol can be instantiated to give a relatively efficient solution which is conceivably usable in practice. We also show that it is i...

• Type: Conference
• Year: 2005
• Where: EUROCRYPT
• Authors: Ran Canetti, Shai Halevi, Jonathan Katz, Yehuda Lindell, Philip D. MacKenzie
• Keywords: Common Reference String, Cryptography, EUROCRYPT 2005, Key Exchange, Password-based Key Exchange