Proactive Secret Sharing And Application Research Without A Trusted Party

Secret sharing has changed the way of traditional key management, and candistract the authority of key management, which improves the security, reliabilityand practicability of the system. Secret sharing has important significance toensuring the storage and transmission security of information, and has become animportant research branch of network security and cryptography.This dissertation firstly introduces the background and status of secret sharing,related mathematical theories, several typical public key cryptosystems, analyzessome different kinds of secret sharing schemes, which focuses on the secret sharingscheme without a trusted party, the proactive secret sharing scheme as well as itscharacteristics. Then, a certification scheme is proposed based on proactive secretsharing without a trusted party.The main work of the dissertation is as following:(1) A certification scheme is proposed based on proactive secret sharingwithout a trusted party. Based on the PKI technology, generating shares and thepublic key, refreshing shares regularly, creating users’ certifications and adding ordeleting members are realized in the scheme.(2) Based on Lagrange Interpolation Polynomial, a refreshment protocol ofshares is proposed, the regular refreshment of shares is realized by producing apolynomial whose constant is zero. New members are added by the shadows ofhonest members’ shares. The new shares can not only resume the secret, but also berefreshed proactively in next refreshment period.(3) Based on Windows XP operating system, a prototype system of the schemeis realized by using Java Language in the development environment of MyEclipse.The experimental results show that the scheme is workable and correct.