Cryptanalysis of Harn-Ren's multi-signature scheme
Jingjing Li, Shixin Zhu · 2010
Harn and Ren proposed an efficient identity based RSA multi-signature scheme published in Journal of Computers and Security. Their scheme is claimed to be the first scheme with both fixed length and verification time. However, we find a flaw in their scheme that potentially allowing an adversary to forge a multi-signature of any group of other users. We gave an improvement of the scheme, and proved the security of the improved version of the scheme.