The Research Of (t,n) Secret Sharing Scheme Against Active Cheating

Secret sharing is an important branch of modern cryptography, andcan effectively ensure the security of information. It plays a key role in keepingsafely, transferring and using important information and confidential data legally. Ithas become the hot topics of research in the field of information security.The secret share exchange is an important part of the secret sharing.Participants to submit the secret share exists the order. If the dishonestparticipant(cheater) submits the secret share at last, it will result in that cheater canrecover the secret,and the honest participant can do noting. It is unfair.At present, the research focus of anti-spoofing secret sharing is how to identifycheaters and the scheme how to prevent cheating behavior is still rare. Preventingthe behavior of recovering secret by cheaters can guarantee the fairnessof the system, so there is an important significance in research. Therefore, a fair (t,n) threshold encryption scheme is proposed, and it can not only identify thecheaters, but also prevent the cheaters to recover the secret so that the fairness ofthe system is guaranteed.The main context is as follows:(1) Firstly, the research background, significance, research statusof secret sharing is presented in the thesis. Several classic anti-spoofing secretsharing was introduced and the future of scheme was analyzed.(2) A fair (t, n) threshold encryption scheme is proposed, in which any userscan encrypt the plaintext with the group public key, and t or more participants canrecover the plaintext cooperatively while fewer than t participants can do nothing.Only getting the decryption factor and shared key can the participants recover thesecret in this scheme. Because the decryption factor and shared key constraintseach other, the scheme does not only identify the cheaters, but also prevent thecheaters recovering the secret, which ensures the fairness of the system.(3) A prototype system is implemented under the compile environment VC++6.0，and the correctness and the availability is verified.