Paper 2009/035

Key-Exposure Free Chameleon Hashing and Signatures Based on Discrete Logarithm Systems

Xiaofeng Chen, Fangguo Zhang, Haibo Tian, Baodian Wei, and Kwangjo Kim


Chameleon signatures simultaneously provide the properties of non-repudiation and non-transferability for the signed message. However, the initial constructions of chameleon signatures suffer from the problem of key exposure. This creates a strong disincentive for the recipient to forge signatures, partially undermining the concept of non-transferability. Recently, some specific constructions of discrete logarithm based chameleon hashing and signatures without key exposure are presented, while in the setting of gap Diffile-Hellman groups with pairings. \indent \,\, In this paper, we propose the first key-exposure free chameleon hash and signature scheme based on discrete logarithm systems, without using the gap Diffile-Hellman groups. This provides more flexible constructions of efficient key-exposure free chameleon hash and signature schemes. Moreover, one distinguishing advantage of the resulting chameleon signature scheme is that the property of ``message hiding" or ``message recovery" can be achieved freely by the signer, $i.e.,$ the signer can efficiently prove which message was the original one if he desires.

Available format(s)
Public-key cryptography
Publication info
Published elsewhere. Unknown where it was published
Chameleon hashingGap Diffie-Hellman groupKey exposure
Contact author(s)
isschxf @ mail sysu edu cn
2009-08-13: last of 2 revisions
2009-01-24: received
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      author = {Xiaofeng Chen and Fangguo Zhang and Haibo Tian and Baodian Wei and Kwangjo Kim},
      title = {Key-Exposure Free Chameleon Hashing and Signatures Based on Discrete Logarithm Systems},
      howpublished = {Cryptology ePrint Archive, Paper 2009/035},
      year = {2009},
      note = {\url{}},
      url = {}
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