Cheater identifiable visual secret sharing scheme

The visual secret sharing scheme proposed by Naor and Shamir provides a way to encrypt a secret black-white image into shares. A qualified group of participants can recover the secret message without using any cryptographic computation. But the original scheme can easily be corrupted by malicious participant. We propose an extension of VSS (visual secret sharing) to identify cheaters before the secret is recovered. Without the need for any additional information and cryptographic computation, every participant can verify the validity of shares of other participants, thus the security of VSS is enhanced.