# A Note on Constant-Round Zero-Knowledge Proofs of Knowledge

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DOI: 10.1007/s00145-012-9132-7

- Cite this article as:
- Lindell, Y. J Cryptol (2013) 26: 638. doi:10.1007/s00145-012-9132-7

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## Abstract

In this note, we show the existence of *constant-round* computational zero-knowledge *proofs of knowledge* for all \(\mathcal {NP}\). The existence of constant-round zero-knowledge proofs was proven by Goldreich and Kahan (Journal of Cryptology, 1996), and the existence of constant-round zero-knowledge *arguments* of knowledge was proven by Feige and Shamir (CRYPTO, 1989). However, the existence of constant-round zero-knowledge proofs of knowledge for all \(\mathcal {NP}\) is folklore, to the best of our knowledge, since no proof of this fact has been published.