Study On Secret Sharing In Information Security

This dissertation expatiates the concepts,research actualities and background of secret sharing system, analyses the security of secret sharing schemes, and puts forward some security hidden troubles that are likely to exist, then constructs secure secret sharing schemes in allusion to the security hidden troubles. Furthermore, the ideas of certificate and indentity are applied in secret sharing schemes, thus, dynamic secret sharing schemes based on certificate and based on identity are put forward.A secure secret sharing scheme that can resist cheating is presented in allusion to the adversaries'Repeat-Recovery attack. Each participant validates his received shadow by using a formula in order to prevent the dealer's dishonesty. At the pooling time, each participant chooses and submits one pair of shadow among his many pairs at random, which holds back the adversaries'filching the secret or the shadows effectively.In dynamic secret sharing schemes based on certificate, each participant's certificate public-key's corresponding private-key is his shadow. The dealer need not transfer secret information to any participant, thus, safe channels are not needed. This system is dynamic, that is to say, multi-secrets can be shared when each participant's shadow has no need to be modified. This system's security is based on the difficulty of large number's factoring and the intractability discrete logarithm problem.An ID-based dynamic threshold secret sharing scheme is proposed based on identity-based cryptography. In this scheme, a group of participants can use each ID-based private key initialized from Key Distribution Centre to share and resume different secrets. The difficulties of solving DLP and computing Diffie-Hellman problems can prevent cheaters'cheating behaviors, and bilinear pairings and ID-based key management makes this scheme operate simply.