Efficient Non-interactive Universally Composable String-Commitment Schemes

  • Authors:
  • Ryo Nishimaki;Eiichiro Fujisaki;Keisuke Tanaka

  • Affiliations:
  • NTT, Tokyo, Japan 180-8585 and Department of Mathematical and Computing Sciences, Tokyo Institute of Technology, Tokyo, Japan 152-8552;NTT, Tokyo, Japan 180-8585;Department of Mathematical and Computing Sciences, Tokyo Institute of Technology, Tokyo, Japan 152-8552

  • Venue:
  • ProvSec '09 Proceedings of the 3rd International Conference on Provable Security
  • Year:
  • 2009

Quantified Score

Hi-index 0.00

Visualization

Abstract

The universal composability (UC) for commitment is a very strong security notion. It guarantees that commitment schemes remain secure even if they are composed with arbitrary protocols and polynomially many copies of the schemes are run concurrently. Several UC commitment schemes in the common reference string (CRS) model have been proposed, but, they are either interactive commitment or bit-commitment (not string-commitment) schemes. We propose new non-interactive string-commitment schemes that achieve UC security in the CRS model assuming the difficulty of the decisional Diffie-Hellman problem or the decisional composite residuosity problem, but our schemes are not reusable. The main building blocks of our constructions are all-but-one trapdoor functions (ABO-TDFs) introduced by Peikert and Waters in STOC 2008 to construct secure public-key encryption schemes. Our main idea is to use the homomorphic properties of the function indices of the all-but-one trapdoor functions and to extend the functions to probabilistic ones by using re-randomization of ciphertexts. This is a new application of ABO-TDFs.