Improved generic construction of chameleon hash to group elements

Abstract

ABSTRACTChameleon hash functions are trapdoor one-way functions with many applications as, for example, off-line/on-line signatures and chameleon signatures. Chameleon signatures are useful to protect privacy of signatures in some business systems where signatures are not allowed to be verified universally, and off-line/on-line signatures are particularly suitable for systems with limited computing resources on-line, but enough computation power off-line, such as in smart card applications. Previous research focused on concrete constructions based on different assumptions, as well as schemes without the key-exposure problem. The main contribution of this paper is a generic construction method of structure-preserving chameleon hash from quasi-adaptive noninteractive zero-knowledge (QANIZK) and two concrete constructions from adaptive sound and simulation sound QANIZK for witness sampleable (WS) distributions proposed by Kiltz and Wee in Eurocrypt 2015, with/without key-exposure respectively. Compared with the constructions from linearly homomorphic structure-preserving signature (LHSPS), our constructions improve the efficiency, the assumptions, as well as the security guarantees.