Traitor Tracing Schemes: a Review

This paper provides a review on traitor tracing schemes that are developed to counter piracy strategies. The review starts with a formal definition of the traitor tracing schemes. The paper is then outlined based on two main strategies which may taken by digital content pirates. Mostly the pirates have strategy to make use leaked decryption key or leaked decrypted content. For each piracy strategy, we presents traitor tracing schemes that can be used to counter the piracy. We also analysis strength and weakness of each group of the schemes. At the end of this paper, we propose to combine some schemes for better protection.

Fully Secure Codes Based Tracing and Revoking Scheme with Constant Ciphertext

In broadcast encryption system certain users may leak their decryption keys to build pirate decoders, so traitor tracing is quite necessary. There exist many codes based traitor tracing schemes. As pointed out by Billet and Phan in ICITS 2008, these schemes lack revocation ability. The ability of revocation can disable identified malicious users and users who fail to fulfill the payments, so that the broadcast encryption system can be more practical. Recently, Zhao and Li presented a construction of codes based tracing and revoking scheme which achieves user revocation as well as traitor tracing. However, their scheme is only secure against chosen plaintext attacks under selective-adversary model with random oracle. In this paper, we obtain a new construction of codes based tracing and revoking scheme which is proved secure against chosen ciphertext attacks under adaptive-adversary model without random oracle. Our idea is to insert codeword into Boneh and Hamburgs identity based broadcast encryption scheme to retain the ability of user revocation and use Boneh and Naors method to trace traitors. Our fully secure scheme is roughly as efficient as Zhao and Lis scheme while the security is enhanced.