Multisignatures with distinguished signing authorities for sequential and broadcasting architectures

In the multisignature scheme with distinguished signing authorities, each group member is responsible for his own signing of a partial message. Recently, Wu and Hsu proposed the multisignature schemes with distinguished signing authorities for sequential and broadcasting architectures. However, in their schemes, the computational complexity for a verifier to verify the multisignature is dependent on the number of members in the group. It is very time-consuming for a verifier to verify the multisignature when the number of group members increases. In this paper, we propose new multisignature schemes with distinguished signing authorities for sequential and broadcasting architectures. In our methods, the computational complexity for a verifier to verify the multisignature will not be significantly affected by the number of signers in the group G. Hence, the verification time for any multisignature is almost equivalent to that of an individual signature.