A fully public-key traitor-tracing scheme

We propose a fully public-key traitor-tracing scheme in which each subscriber can choose his or her own private decryption key without others learning the key. The distributor of the digital content utilizes the public data coming from all subscribers to compute a public encryption key. The paid contents are then transmitted to the subscribers, after being encrypted with the public key. Each subscriber can decrypt the data using his or her own secret key. Even if a coalition of subscribers conspire to create a pirate decoder with a tamper-free decryption key, we have a tracing algorithm to trace them. Our scheme is long-lived, which means that the subscribers’ secret keys need not be regenerated after the pirate key is detected or when subscribers join or leave the system. Finally, our scheme guarantees anonymity