Designated Con rmer Signatures Revisited

نویسنده

  • Douglas Wikström
چکیده

Previous de nitions of designated con rmer signatures in the literature are incomplete, and the proposed security de nitions fail to capture key security properties, such as unforgeability against malicious con rmers and non-transferability. We propose new de nitions. Previous schemes rely on the random oracle model or set-up assumptions, or are secure with respect to relaxed security de nitions. We construct a practical scheme that is provably secure with respect to our security definition under the strong RSA-assumption, the decision composite residuosity assumption, and the decision Di e-Hellman assumption. To achieve our results we introduce several new relaxations of standard notions. We expect these techniques to be useful in the construction and analysis of other e cient cryptographic schemes.

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Designated Conrmer Signatures Revisited * Douglas Wikström

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تاریخ انتشار 2006