An efficient buyer-seller watermarking protocol based on proxy signatures

In this paper, we employ the concept of proxy signatures to propose a buyer-seller watermarking protocol. We show that in the proposed protocol, watermarks are generated such that the seller is unable to fabricate piracy, but he can trace copyright violators. The protocol further protects anonymity of the buyer until s/he is adjudicated to be guilty. Moreover, we solve the conspiracy problem without imposing any unrealistic assumptions about thrust-worthiness of the parties involved.