The Study Of (k, N) Threshold Secret Sharing Scheme And Its Application

Secret sharing is an important tool for the information security and the data privacy, and it plays an important role in protecting important information and secret data from being lost,destroyed,viciously modified,or into wrong hands.The(k,n) threshold secret sharing system is the most useful system for its good properties.It can not only prevent the excessive concentration power from being abused but also guarantee the security and integrity of the secret if it used for keeping secret.Therefore,the system is efficient in key management.Threshold signature is a special digital signature based on secret sharing technology.It is provided with the fascinating properties of duty partaking,right distributing and trust sharing,so it can meet the needs of some specific environment.This thesis reviews the backgrounds and research advances of the secret sharing and analyzes some of the existing threshold schemes from various angles,including the channel efficiency,verification of the threshold scheme and the security of the multi-verifiable secret sharing scheme.Then,aiming at these problems,we design some practical and secure secret sharing schemes according to our known knowledge.Moreover, we study its application in key transport and digital signature,and analyze shortcoming of most of the existing scheme and design the improvement schemes.Firstly,we analyze a threshold secret sharing based on partial broadcast channels and point out its imperfections.Then we propose the improvement scheme which reduces the number of the channels and brings down the total communications compared with the existing schemes.In the basis of that,a secure and efficient verifiable secret sharing scheme is proposed.It has verification prosperity and has the advantage of the number of channels and the total communications needed compared with the existing vss schemes. Secondly,many of verifiable multi-secret sharing schemes has been studied and a secure shortcoming been pointed out in two of these schemes.Aiming at the problem,an improvement vmss scheme is proposed which overcoming the secure shortcoming of the original scheme.Then we implement some of these schemes.Thirdly,we study its application in key transport,analyze a key transport protocol based on propositioned secret sharing,and point out security problems in this scheme.Then,taking advantage of verifiable secret sharing and digital signatures,an improvement scheme which can avoid insufficiency of the original scheme is proposed in this paper.The scheme is more secure than the original scheme.Finally,we study threshold signature and find out that most of schemes existing the conspiracy attack and updating efficiency problem.A threshold signature scheme with high updating efficiency which can withstand the conspiracy attack is proposed.