Abstract: The session key S is divided into the sum of S₁ and S₂. Under the condition of a large integer factoring problem, S₁ is decrypted by constructing a special equation(scheme 1). Under the condition of a discrete logarithm problem, S₂ is decrypted by the OPE (Oblivious Polynomial Evaluation) protocol and Lagrange Interpolation Polynomial (scheme 2). On the basis of a linearly additive combination of scheme 1 and scheme 2, a new traitor tracing scheme is formed, which has advantages of both of them, and meanwhile overcomes their disadvantages. It has many advantages such as multi-service, collusion-resistance, asymmetry, black-box tracing, forward-security and backward-security, and its compositive performance is also better than those of existing ones.

Key words: multiple-service, collusion-resistance, asymmetric, black-box tracing, forward-security