Modified fully public-key traitor tracing schemes

Lyuu et al [1] presented a fully public-key traitor tracing scheme based on Chinese Remainder Theorem; In terms of security, the scheme is basically equivalent to the ElGamal cryptosystem. They also presented a possible way of forging decryption keys. In this paper, we propose two modified traitor tracing schemes and a corresponding tracing algorithm which can trace all the traitors contributing to the pirate decoder. The proposed schemes have all the advantages of the original scheme. In addition, one of our proposed schemes can save nearly half the communication bandwidth, and the other enhances the security of the original scheme. Further our proposed schemes are feasible to be used to construct multi-channel pay-TV schemes.