Pretty-Simple Password-Authenticated Key-Exchange Protocol Proven to be Secure in the Standard Model

Kazukuni KOBARA  Hideki IMAI  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E85-A   No.10   pp.2229-2237
Publication Date: 2002/10/01
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Information Theory and Its Applications)
Category: Information Security
entropy of passwords,  key exchange,  authentication,  DDH problem,  standard model,  

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In this paper, we propose a pretty-simple password-authenticated key-exchange protocol, which is proven to be secure in the standard model under the following three assumptions. (1) DDH (Decision Diffie-Hellman) problem is hard. (2) The entropy of the password is large enough to avoid on-line exhaustive search (but not necessarily off-line exhaustive search). (3) MAC is selectively unforgeable against partially chosen message attacks, (which is weaker than being existentially unforgeable against chosen message attacks).