International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: On the Security of Some Proxy Signature Schemes

Hung-Min Sun
Bin-Tsan Hsieh
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Abstract: Digital signature scheme is an important research topic in cryptography. An ordinary digital signature scheme allows a signer to create signatures of documents and the generated signatures can be verified by any person. A proxy signature scheme, a variation of ordinary digital signature scheme, enables a proxy signer to sign messages on behalf of the original signer. To be used in different applications, many proxy signatures were proposed. In this paper, we review Lee et al.'s strong proxy signature scheme, multi-proxy signature scheme, and its application to a secure mobile agent, Shum and Wei's privacy protected strong proxy signature scheme, and Park and Lee's nominative proxy signature scheme, and show that all these proxy signature schemes are insecure against the original signer's forgery. In other words, these schemes do not possess the unforgeability property which is a desired security requirement for a proxy signature scheme.
  title={On the Security of Some Proxy Signature Schemes},
  booktitle={IACR Eprint archive},
  keywords={Cryptanalysis, Digital Signature},
  note={ 12178 received 11 Apr 2003, last revised 6 May 2003},
  author={Hung-Min Sun and Bin-Tsan Hsieh},