Cryptology ePrint Archive: Report 2012/382

On the Joint Security of Signature and Encryption Schemes under Randomness Reuse: Efficiency and Security Amplification

Afonso Arriaga and Manuel Barbosa and Pooya Farshim

Abstract: We extend the work of Bellare, Boldyreva and Staddon on the systematic analysis of randomness reuse to construct multi-recipient encryption schemes to the case where randomness is reused across different cryptographic primitives. We find that through the additional binding introduced through randomness reuse, one can actually obtain a security amplification with respect to the standard black-box compositions, and achieve a stronger level of security. We introduce stronger notions of security for encryption and signatures, where challenge messages can depend in a restricted way on the random coins used in encryption, and show that two variants of the KEM/DEM paradigm give rise to encryption schemes that meet this enhanced notion of security. We obtain a very efficient signcryption scheme that is secure against insider attackers without random oracles.

Category / Keywords: public-key cryptography / Randomness reuse, Signcryption, Insider Security.

Publication Info: Full version of the paper published at ACNS 2012.

Date: received 8 Jul 2012, last revised 8 Jul 2012

Contact author: mbb at di uminho pt

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Version: 20120711:163448 (All versions of this report)

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