Formal Model of Proxy Multi-Signature and a Construction
Zhenfu Cao · Chinese Journal of Computers · 2006
As a variation of ordinary digital signature scheme,a proxy signature scheme enables a proxy signer to sign messages on behalf of the original signer.Proxy multi-signature is an extension of the basic proxy signature primitive,and permit two or more entities to delegate their signing capabilities to the same other entity.Although many proxy multi-signature schemes have been proposed since 2000,to date,no precise definitions or proofs of security have been provided for them.In this paper,the authors give the syntax of proxy multi-signature schemes and formalize a notion of security for them.The authors also construct a concrete scheme which is provably-secure assuming the underlying groups are bilinear group pair and the computational Co-Diffie-Hellman problem is hard.Furthermore,the new scheme is very simple and has the property that the size of a proxy multi-signature is independent of the number of the original signers.