New Efficient Non-malleable Commitment Schemes

Non-malleable commitment is recently one of research focuses in international cryptographic community. It has many important applications in e-commerce, and plays important role in constructing other cryptographic protocols. Most existing non-malleable commitment schemes are constructed by requiring that a committer proves, by zero-knowledge proof, that he knows his committed secret. The attached zero-knowledge proof process makes existing non-malleable commitments have higher computational and communication complexity. More efficient schemes are appealing. This paper constructs three new efficient non-malleable commitment schemes which do not require that a committer proves he knows his committed secret by zero-knowledge proof, but rather require a committer proves, by other arguments, that he does know the secret at the same time he makes commitment. These non-malleable commitment schemes, without zero-knowledge proof, are much more efficient.