The Research Of Secret Sharing Among Weighted Participants

Secret sharing scheme is an important branch of modern cryptography. Shamir and Blakley proposed the concept of the threshold secret sharing separately in 1979, since then domestic and foreign scholars have made a lot of research in secret sharing and proposed a number of effective schemes. Existing secret sharing scheme mostly based on the equal status and right of every participant. Actually every participant has different power on the shared secret, therefore the research of secret sharing among weighted participant has extensive practical significance.The dissertation reviews the research advances and the current situation of secret sharing, existing secret sharing scheme mostly based on ECC have the following drawbacks:the dealer chooses and delivers secret information to every participant, a secure channel between them is necessary, and the scheme can't check whether each participant provides the true information. Meanwhile, available documents have few researches on secret sharing among weighted participants, In the existing secret sharing schemes among weighted participants have the following drawbacks:the dealer had too large power, a secure channel is necessary, and they have too large communication. Aiming at these problems, the paper proposed a verifiable multi-secret sharing scheme based on ECC, and two secret sharing schemes among weighted participant. The main results are as follows:1. The paper proposes a verifiable multi-secret sharing scheme based on ECC. Each participant's secret shadow is selected and kept by the participant himself. And the shadows don't need to be changed when the shared secret is renewed, and many secrets can be recovered at one time. The scheme can check whether each participant provides the true information, if any participant provides a false share or attacker tamper the message, they can't gain any message about the shared secret, so a secure channel between them is unnecessary.2. Considering the different power of every participant on shared secret, the paper proposes a dynamic threshold multi-secret sharing scheme among weighted participants based on Chinese remainder theorem. Each participant's secret shadow is selected and kept by the participant himself and the shadows don't need to change when the shared secret is renewed, and many secrets can be recovered in one time. Dealer can check whether each participant provides the true information, and a participant can be freely accepted or fired, so a secure channel between them is unnecessary.3. Considering the different weight of every participant, the paper proposes a (m+n1+n2+…+nl,t+t1+t2+…tl) threshold secret sharing scheme among weighted participants based on Chinese remainder theorem. Each participant's secret shadow is selected and kept by the participant himself and the sub-secret of every participant can be used many times. A secure channel between the dealer and participants is unnecessary. Furthermore, a participant can be freely accepted or fired, many secrets can be recovered in one time.