Perfect Hiding and Perfect Binding Universally Composable Commitment
Schemes with Constant Expansion Factor
Ivan B. Damgård
October 2001 |
Abstract:
Canetti and Fischlin have recently proposed the security notion
universal composability for commitment schemes and provided two
examples. This new notion is very strong. It guarantees that security is
maintained even when an unbounded number of copies of the scheme are running
concurrently, also it guarantees non-malleability, resilience to selective
decommitment, and security against adaptive adversaries. Both of their
schemes uses
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We
present new universally composable commitment schemes based on the Paillier
cryptosystem and the Okamoto-Uchiyama cryptosystem. The schemes are
efficient: to commit to We also show how the schemes can be applied to do efficient zero-knowledge proofs of knowledge that are universally composable Available as PostScript, PDF, DVI. |