An improved multi-signature scheme for specified group of verifiers

摘要

Zhang and Xiao presented a multi-signature scheme for a specified group of verifiers and showed that forging their signature is mathematically equivalent to forge Harn's signature. However, Zhang and Xiao's scheme is not secure against the rogue-key attack. In this paper, we show how to mount a rogue-key attack on Zhang and Xiao's scheme and propose an improved multi-signature scheme for a specified group of verifiers. Our new scheme not only inherits the advantages of Zhang and Xiao's scheme, but also resists to known attacks including the rogue-key attack.