The Research And Realization Of Multi-secret Sharing Against Cheating

With the development of network technology and cryptology, the requirement of the cryptology system becomes different for various environments. Threshold secret sharing system can improve system's security and robustness by distributing the responsibility, which is different from the traditional system.Threshold secret sharing's generation, development and applications in various fields have been introduced. The verifiable secret sharing scheme and multi-secret sharing scheme have been discussed in detail. To deal with the problems and deficiency of these schemes, we provide a new multi-secret sharing scheme against cheating which has the following features:1. Dealer can add and delete members in secret sharing. This means our scheme has great flexibility. The only thing needed for deleting members is to change the public information on NB, which doesn't affect other members' shadow.2. A member can obtain many shadows from a secret key in the initial stage by certain algorithm. This can easily extend our scheme to be one with priviledge subsets. To obtain more shadows in one secret sharing process or participate secret sharing many times, members only need one unchangeable secret key and some public information.3. This scheme can detect the cheating of illegal members and use zero-knowledge proof to stop an illegal member from recovering the secret.We analyze the key algorithms of our scheme, such as big number calculation, big prime choice algorithm, generator choice algorithm, Hash function, Lagrange interpolation algorithm in Galois field and so on. We use VC++ 6.0 and SQL Server2000 to design a prototype system in windows XP. The result shows that our scheme which has good security and robustness, is right and feasible. At last, we summarize our dissertation and expect the future of threshold secret sharing.