## Cryptology ePrint Archive: Report 2007/396

Proxy Re-Signature Schemes without Random Oracles

Jun Shao and Zhenfu Cao and Licheng Wang and Xiaohui Liang

Abstract: To construct a suitable and secure proxy re-signature scheme is not an easy job, up to now, there exist only three schemes, one is proposed by Blaze et al. at EUROCRYPT 1998, and the others are proposed by Ateniese and Hohenbergerat ACM CCS 2005. However, none of these schemes is proved in the standard model (i.e., do not rely on the random oracle heuristic). In this paper, based on Waters' approach, we first propose a multi-use bidirectional proxy re-signature scheme, denoted as $S_{mb}$, which is existentially unforgeable in the standard model. And then, we extend $S_{mb}$ to be a multi-use bidirectional ID-based proxy re-signature scheme, denoted by $S_{id-mb}$, which is also existentially unforgeable in the standard model. Both of these two proposed schemes are computationally efficient, and their security bases on the Computational Diffie-Hellman (CDH) assumption.

Category / Keywords: public-key cryptography / proxy re-signature

Publication Info: Indocrypt 2007

Date: received 12 Oct 2007, last revised 15 Jul 2008

Contact author: chn junshao at gmail com

Available format(s): PDF | BibTeX Citation

Note: S_{mu} scheme is revised according to an attack.

Short URL: ia.cr/2007/396

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