A Few Kinds Of Special Research Of Threshold Signature

In21century, with the rapid development of information era, information has become the important strategic resources of society. The network and the popularization of computer application more promoted the development of informationization, however, there is a serious problem that is the security problem of the information. And the integrity of the digital document, the authentication and undeniable is the most basic requirements of the safety of the informatization, At the same time it also decides to the further development of the informatization. Digital signature is an important branch of cryptography research, it also meets the safety requirements as one of the important means. At present digital signature technology has penetrated into multiple field of research, and in the real environment it has been used widely, especially in the network environment. According to the different application purpose, digital signatures have many kinds of classification, and this paper mainly introduces the threshold signature.Desmedt et al put forward threshold signature scheme in1991for the first time, Threshold signature system put the secret sharing technology into the digital signature of the formation of a special signature system. In the threshold signature scheme, the participant with their own hands signed by the master of secret share of calculation news "part of the signature", Used for synthesis final threshold signature.This paper first introduces the related research and development of digital signature and threshold signature, then introduces the mathematical knowledge and cryptography knowlege which is related to our research. The main contents are as follows:1. It analysis a threshold-signature with proxy signers, find out the signature can not meet strong unforgeability. This makes the original signatory or external attacker can forge an effective signature. This paper proposes an improvement scheme on the basis of the original one. The new scheme not only inherits the advantages of the original plan and meet the strong non-forgeability.2. Our paper made a deeply safety analysis to a improved of a threshold signature scheme with no trusted center, points out that there are still the improved security flaws. Because the plan cannot resist the external attacks and replace against public key. This paper through a deeper level of research, and gives a further improvement, the new improved scheme is secure and effective.