We introduce and define the notion of identity-based zero-knowledge, concentrating on the non-interactive setting. In this setting, our notion allows any prover to widely disseminate a proof of a statement while protecting the prover from plagiarism in the following sense: although proofs are transferable (i.e., publicly verifiable), they are also bound to the identity of the prover in a way which is recognizable to any verifier. Furthermore, an adversary is unable to change this identity (i.e., to claim the proof as his own, or to otherwise change the authorship), unless he could have proved the statement on his own.
While we view the primary contribution of this work as a formal definition of the above notion, we also explore the relation of this notion to that of non-malleable (non-interactive) zero-knowledge. On the one hand, we show that these two notions are incomparable: that is, there are proof systems which are non-malleable but not identity-based, and vice versa. On the other hand, we show that a proof system of either type essentially implies a proof system of the other type.
KeywordsProof System Common Reference String Interactive Proof System Trapdoor Permutation Universally Composable Framework
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- 1.Barak, B.: Constant-Round Coin-Tossing with a Man in the Middle or Realizing the Shared Random String Model. In: FOCS (2002)Google Scholar
- 2.Blum, M.: How to Prove a Theorem so No One Else Can Claim It. In: Proceedings of the International Congress of Mathematicians (1986)Google Scholar
- 3.Blum, M., Feldman, P., Micali, S.: Non-Interactive Zero-Knowledge and Its Applications. In: STOC (1988)Google Scholar
- 4.Canetti, R.: Universally Composable Security: A New Paradigm for Cryptographic Protocols. In: FOCS (2001)Google Scholar
- 5.Cramer, R., Damgård, I.: Fast and Secure Immunization Against Adaptive Man-in-the-Middle Impersonation. In: Fumy, W. (ed.) EUROCRYPT 1997. LNCS, vol. 1233, pp. 75–87. Springer, Heidelberg (1997)Google Scholar
- 10.Jakobsson, M., Sako, K., Impagliazzo, R.: Designated-Verifier Proofs and their Applications. In: Maurer, U.M. (ed.) EUROCRYPT 1996. LNCS, vol. 1070, pp. 143–154. Springer, Heidelberg (1996)Google Scholar
- 11.Katz, J., Ostrovsky, R., Smith, A.: Round Efficiency of Multi-Party Computation with a Dishonest Majority. In: Biham, E. (ed.) EUROCRYPT 2003. LNCS, vol. 2656, Springer, Heidelberg (2003)Google Scholar
- 13.Ostrovsky, R., Wigderson, A.: One-Way Functions are Essential for Non-Trivial Zero-Knowledge. In: 2nd Israeli Symp. on Theory of Computing and Systems (1993)Google Scholar
- 15.Pass, R.: Bounded-Concurrent Multi-Party Computation with a Dishonest Majority. In: STOC (2004)Google Scholar
- 16.Sahai, A.: Non-Malleable Non-Interactive Zero Knowledge and Adaptive Chosen-Ciphertext Security. In: FOCS (1999)Google Scholar