Cryptology ePrint Archive: Report 2009/298

Cryptanalysis of Certificateless Signcryption Schemes and an Efficient Construction Without Pairing

S.Sharmila Deva Selvi and S.Sree Vivek and C.Pandu Rangan

Abstract: Certificateless cryptography introduced by Al-Riyami and Paterson eliminates the key escrow problem inherent in identity based cryptosystems. Even though building practical identity based signcryption schemes without bilinear pairing are considered to be almost impossible, it will be interesting to explore possibilities of constructing such systems in other settings like certificateless cryptography. Often for practical systems, bilinear pairings are considered to induce computational overhead. Signcryption is a powerful primitive that offers both confidentiality and authenticity to noteworthy messages. Though some prior attempts were made for designing certificateless signcryption schemes, almost all the known ones have security weaknesses. Specifically, in this paper we demonstrate the security weakness of the schemes in \cite{BF08}, \cite{DRJR08} and \cite{CZ08}. We also present the first provably secure certificateless signcryption scheme without bilinear pairing and prove it in the random oracle model.

Category / Keywords: Certificateless Signcryption, Cryptanalysis, Provable Security, Bilinear Pairing, Pairing-free Certificateless Signcryption.

Publication Info: This paper got accepted in INSCRYPT 2009, held on Dec 12-15, 2009.

Date: received 22 Jun 2009, last revised 14 Jun 2010

Contact author: ssreevivek at gmail com,sharmioshin@gmail com

Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | PDF | BibTeX Citation

Version: 20100615:050255 (All versions of this report)

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