Cryptology ePrint Archive: Report 2006/267
Stateful Public-Key Cryptosystems: How to Encrypt with One 160-bit Exponentiation
Mihir Bellare and Tadayoshi Kohno and Victor Shoup
Abstract: We show how to significantly speed-up the encryption portion
of some public-key cryptosystems by the simple expedient of allowing a
sender to maintain state that is re-used across different encryptions.
In particular we present stateful versions of the DHIES and
Kurosawa-Desmedt schemes that each use only one exponentiation to
encrypt, as opposed to two and three respectively in the original
schemes, yielding the fastest discrete-log based public-key encryption
schemes known in the random-oracle and standard models respectively.
The schemes are proven to meet an appropriate extension of the
standard definition of IND-CCA security that takes into account novel
types of attacks possible in the stateful setting.
Category / Keywords: public-key cryptography /
Publication Info: Preliminary version in ACM CCS 2006. This is the full version.
Date: received 12 Aug 2006, last revised 12 Aug 2006
Contact author: mihir at cs ucsd edu
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Version: 20060812:172715 (All versions of this report)
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