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Security analysis of KEA authenticated key exchange protocol. (English) Zbl 1151.94532

Yung, Moti (ed.) et al., Public key cryptography – PKC 2006. 9th international conference on theory and practice of public-key cryptography, New York, NY, USA, April 24–26, 2006. Proceedings. Berlin: Springer (ISBN 3-540-33851-9/pbk). Lecture Notes in Computer Science 3958, 378-394 (2006).
Summary: KEA is a Diffie-Hellman based key-exchange protocol developed by NSA which provides mutual authentication for the parties. It became publicly available in 1998 and since then it was neither attacked nor proved to be secure. We analyze the security of KEA and find that the original protocol is susceptible to a class of attacks. On the positive side, we present a simple modification of the protocol which makes KEA secure. We prove that the modified protocol, called KEA\(+\), satisfies the strongest security requirements for authenticated key-exchange and that it retains some security even if a secret key of a party is leaked. Our security proof is in the random oracle model and uses the Gap Diffie-Hellman assumption. Finally, we show how to add a key confirmation feature to KEA\(+\) (we call the version with key confirmation KEA\(+\)C) and discuss the security properties of KEA\(+\)C.
For the entire collection see [Zbl 1102.94003].

MSC:

94A60 Cryptography
94A62 Authentication, digital signatures and secret sharing

Software:

HMQV
Full Text: DOI