Threshold Multi-Proxy Multi-Signature Scheme Based on Bilinear Pairings

摘要

In a conventional proxy signature scheme, a delegated person called the proxy signer can sign a document on behalf of the original signer such that any verifier can validate the proxy signature. When applied to group oriented operations, proxy signature schemes can be categorized into several forms according to the predefined signing policies. Consider the flexibility of delegation; threshold multi-proxy multi-signature (TMPMS) schemes might be the best solution. In a (t{sub}1{sub}1-t{sub}2{sub}2) TMPMS scheme, any t{sub}1 out of n{sub}1 original signers can authorize n{sub}2 members as the proxy signers, such that any t{sub}2 out of t{sub}2 proxy signers can produce a valid proxy signature on behalf of the original group. The security of previously proposed schemes is primarily based on the hardness of inverting either the discrete logarithms or the factorization. Based on bilinear pairings, a new TMPMS scheme is proposed in this paper. The proposed scheme has the merit that it does not require the trusted third party to distribute the secret. Further, it also preserves the anonymity of the actual original and the proxy signers, i.e., only the original and the proxy groups are identified.