Universally composable commitments

  • We propose a new security measure for commitment protocols, called Universally Composable (UC) Commitment. The measure guarantees that commitment protocols behave like an \ideal commitment service," even when concurrently composed with an arbitrary set of protocols. This is a strong guarantee: it implies that security is maintained even when an unbounded number of copies of the scheme are running concurrently, it implies non-malleability (not only with respect to other copies of the same protocol but even with respect to other protocols), it provides resilience to selective decommitment, and more. Unfortunately two-party uc commitment protocols do not exist in the plain model. However, we construct two-party uc commitment protocols, based on general complexity assumptions, in the common reference string model where all parties have access to a common string taken from a predetermined distribution. The protocols are non-interactive, in the sense that both the commitment and the opening phases consist of a single message from the committer to the receiver.

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Author:Ran Canetti, Marc Fischlin
Document Type:Preprint
Year of Completion:2005
Year of first Publication:2001
Publishing Institution:Universit├Ątsbibliothek Johann Christian Senckenberg
Release Date:2005/07/20
Tag:Commitment schemes; concurrent composition; non-malleability; security analysis of protocols
Preprint, sp├Ąter in: Advances in Cryptology - Crypto 2001 , Lecture Notes in Computer Science, Vol. 2139, pp. 19-40, Springer-Verlag, 2001
Source:Advances in Cryptology - Crypto 2001 , Lecture Notes in Computer Science, Vol. 2139, pp. 19-40, Springer-Verlag, 2001 , http://www.mi.informatik.uni-frankfurt.de/research/papers/fischlin.composable.2001.pdf
Institutes:Informatik und Mathematik / Mathematik
Informatik und Mathematik / Informatik
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 51 Mathematik / 510 Mathematik
Licence (German):License LogoDeutsches Urheberrecht