Fully collusion-resistant traitor tracing scheme with shorter ciphertexts

Abstract

A traitor tracing scheme allows a content distributor to detect at least one of the traitors whose secret key is used to create a pirate decoder. In building efficient traitor tracing schemes, reducing ciphertext size is a significant factor since the traitor tracing scheme must handle a larger number of users. In this paper, we present a fully collusion-resistant traitor tracing scheme where the ciphertext size is 2.8 times shorter and encryption time is 2.6 times faster, compared to the best cases of fully collusion-resistant schemes previously suggested. We can achieve these efficiency results without sacrificing other costs. Also, our scheme supports public tracing and black-box tracing. To achieve our goal, we use asymmetric bilinear maps in prime order groups, and we introduce a new cancellation technique that has the same effect as that in composite order groups.