A Multisignature Scheme with Distinguished Signing Authorities

Abstract

Multisignature is an extension of digital signature, where a group of signers jointly produce a valid signature on a message. Distinguished Signing authorities were first introduced by L.Harn. In Distinguished signing authorities, each of the signers is responsible for only one part of the message rather than the whole message itself. Along with the group of signers, we also have a trusted clerk who verifies the individual signatures and generates the final multisignature. We extensively studied the two existing schemes proposed by Harn and Hwang. Although Hwnag’s scheme overcame all the drawbacks of Harn’s scheme, it has drawbacks like high computational cost and communication overhead. So, we proposed a modification over Hwang’s scheme taking into consideration the signature length, computational complexity of signature generation and the cost of signature verification. The performance evaluation of the proposed scheme was theoretically compared to that of the Hwang’s scheme. Both the schemes are implemented to calculate the signature length and the execution time required for different phases in the multisignature scheme. Hence these implementation results were useful to verify the performance evaluation.