On the Exact Security of Multi-signature Schemes Based on RSA

Up to present, we have yet seen no multi-signature schemes based on RSA secure against active attacks proposed. We have examined the possibility of simulation of signatures in the MM scheme [7] in order to investigate whether that scheme has the security against active attacks. The MM scheme cannot be shown secure against active attacks. We have constructed the RSA-based multi-signature scheme in order to overcome the problem that the MM scheme has. The proposed scheme provides the security against adaptive chosen message insider attack targeting one signer, and can keep tighter reduction rate.