Cryptology ePrint Archive: Report 2003/111

Further Cryptanalysis of some Proxy Signature Schemes

Jiqiang Lv and Jingwei Liu and Xinmei Wang

Abstract: Proxy signature is a signature that an original signer delegates his or her signing capability to a proxy signer, and then the proxy signer creates a signature on behalf of the original signer. However, Sun et al.[7] showed that the proxy and multi-proxy signatures of Lee et al.[3], and the strong proxy signature scheme with proxy signer privacy protection of Shum et al.[6] are not against the original signer's forgery attack, so these schemes do not process the property of unforgeability. In this paper, we present an extensive forgery method on these schemes, which makes the forgery method of Sun et al.be a special case of ours.

Category / Keywords: Public Key Cryptography; Proxy Digital Signature; Forgery Attack

Date: received 29 May 2003, last revised 2 Jan 2004, withdrawn 7 Jan 2006

Contact author: lvjiqiang at hotmail com

Available format(s): (-- withdrawn --)

Note: revise a paper

Version: 20060107:103211 (All versions of this report)

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