Cheating detection and cheater identification in secret sharing schemes

Abstract

A threshold scheme for secret sharing can protect a secret with high reliability and flexibility. These advantages can be achieved only when all the participants are honest, i.e. all the participants willing to pool their shadows shall always present the true ones. Cheating detection is an important issue in the secret sharing scheme. However, cheater identification is more effective than cheating detection in realistic applications. If some dishonest participants exist, the other honest participants will obtain a false secret, while the cheaters may individually obtain the true one. The paper presents a method to enforce the security of any threshold scheme with the ability to detect cheating and identify cheaters. By applying a one-way hashing function along with the use of arithmetic coding, the proposed method can be used to deterministically detect cheating and identify the cheaters, no matter how many cheaters are involved in the secret reconstruction.