Cryptology ePrint Archive: Report 2008/187

An Efficient and Provably Secure ID-Based Threshold Signcryption Scheme

Fagen Li and Yong Yu

Abstract: Signcryption is a cryptographic primitive that performs digital signature and public key encryption simultaneously, at a lower computational costs and communication overheads than the signature-then-encryption approach. Recently, two identity-based threshold signcryption schemes[12],[26] have been proposed by combining the concepts of identity-based threshold signature and signcryption together. However, the formal models and security proofs for both schemes are not considered. In this paper, we formalize the concept of identity-based threshold signcryption and give a new scheme based on the bilinear pairings. We prove its confidentiality under the Decisional Bilinear Diffie-Hellman assumption and its unforgeability under the Computational Diffie-Hellman assumption in the random oracle model. Our scheme turns out to be more efficient than the two previously proposed schemes.

Category / Keywords: public-key cryptography /

Publication Info: ICCCAS 2008

Date: received 26 Apr 2008, last revised 7 Apr 2009

Contact author: fagenli at uestc edu cn

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Version: 20090407:071613 (All versions of this report)

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