CryptoDB

Paper: Accumulating Composites and Improved Group Signing

Authors: Gene Tsudik Shouhuai Xu URL: http://eprint.iacr.org/2003/112 Search ePrint Search Google Constructing practical and provably secure group signature schemes has been a very active research topic in recent years. A group signature can be viewed as a digital signature with certain extra properties. Notably, anyone can verify that a signature is generated by a legitimate group member, while the actual signer can only be identified (and linked) by a designated entity called a group manager. Currently, the most efficient group signature scheme available is due to Camenisch and Lysyanskaya \cite{CL02}. It is obtained by integrating a novel dynamic accumulator with the scheme by Ateniese, et al. \cite{ACJT00}. In this paper, we construct a dynamic accumulator that accumulates \emph{composites}, as opposed to previous accumulators that accumulated \emph{primes}. We also present an efficient method for proving knowledge of factorization of a committed value. Based on these (and other) techniques we design a novel provably secure group signature scheme. It operates in the \emph{common auxiliary string} model and offers two important benefits: 1) the {\sf Join} process is very efficient: a new member computes only a single exponentiation, and 2) the (unoptimized) cost of generating a group signature is 17 exponentiations which is appreciably less than the state-of-the-art.
BibTeX
@misc{eprint-2003-11827,
title={Accumulating Composites and Improved Group Signing},
booktitle={IACR Eprint archive},
keywords={applications / Accumulator, group signature, identity escrow},
url={http://eprint.iacr.org/2003/112},
note={ shxu@ics.uci.edu 12202 received 30 May 2003},
author={Gene Tsudik and Shouhuai Xu},
year=2003
}