The Relationship Between Password-Authenticated Key Exchange and Other Cryptographic Primitives

Abstract. We consider the problem of password-authenticated key exchange (PAK) also known as session-key generation using passwords: constructing session-key generation protocols that are secure against active adversaries (person-in-the-middle) and only require the legitimate parties to share a low-entropy password (e.g. coming from a dictionary of size poly(n)). We study the relationship between PAK and other cryptographic primitives. The main result of this paper is that password-authenticated key exchange and public-key encryption are incomparable under black-box reductions. In addition, we strengthen previous results by Halevi and Krawczyk [14] and Boyarsky [5] and show how to build key agreement and semi-honest oblivious transfer from any PAK protocol that is secure for the Goldreich-Lindell (GL) definition [11]. We highlight the difference between two existing definitions of PAK, namely the indistinguishability-based definition of Bellare, Pointcheval and Rogaway (BPR) [1] an...

• Type: Conference
• Year: 2005
• Where: TCC
• Authors: Minh-Huyen Nguyen
• Keywords: Cryptography, Password-authenticated Key Exchange, Semi-honest Oblivious Transfer, Session-key Generation, TCC 2005