Cryptanalysis of Threshold Proxy Signature Schemes 1 )
نویسنده
چکیده
A (t, n) threshold proxy signature scheme enables an original signer to delegate the signature authority to a proxy group of n member such that t or more than t proxy signers can cooperatively sign messages on behalf of the original signer. In the paper, we review the security of two nonrepudiable threshold proxy signature schemes. We show that Tzeng et al.’s threshold proxy signature scheme is insecure against a malicious original signer’s forgery and that Hsu et al.’s threshold proxy signature scheme is universally forgeable. In other words, neither of the above-mentioned threshold proxy signature schemes holds the unforgeability and provides non-repudiation as claimed.
منابع مشابه
Cryptanalysis of Nonrepudiable Threshold Proxy Signature Schemes with Known Signers
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