Abstract: This paper presented a new symmetry scheme of traitor tracing．Based on the broadcast encryption techniques and Hash function theory,the corresponding key scheme,encryption scheme,decryption scheme and traitor tracing algorithm were constructed in this paper．The proper values of system parameters were obtained by the Chernoff bound．The scheme in this paper has the advantages of lower storing complexity of personal key,lower user computing complexity and less data redundancy than existing CFN symmetry schemes and it can efficiently combat against the collusion key attack in the broadcast encryption.

Key words: Broadcast encryption,Traitor tracing,Collusion key attack,Chernoff bound,Hash function