Secure Traceable (t, N) Threshold Signature Scheme

With the rapid development of information technology, information security is gaining increasing concern. Digital signature has been in common use today. Threshold scheme has opened the door for key agreement and key management. Threshold signature scheme is devised based on the threshold schemes by Desmedt and Frankle in 1990's. Many researchers have shown great interest because of its high practical value.We propose a new secure traceable (t, n) threshold signature scheme in this paper. It borrows the construction idea of partition and group keys. It get the group signature by employing the modified ElGamal signature scheme that is based on discrete logarithms and hash functions.The security and practicality of the new sheme is improved without KAC that cheat of KAC is prevented. With the tracibility the identities of signers can be revealed recurring to the trusted key authentication center when it is nessary and the application-bound of threshold signature scheme is enlarged mostly.The security of the new signature scheme is analyzed in detail. We demonstrate that the key and the partition signature is secure, and the scheme is robust. It is also shown that the partition signatures can not be forged, and the scheme is secure under the conspiracy attack.