In broadcast encryption schemes, traceability is a useful property to trace authorized subscribers, called traitors, who collude for manufacturing a pirate decoder. Unfortunately, this is usually achieved with a sacrifice of a privacy. Most traitor tracing schemes in the literature have been developed without considering a subscriber's anonymity, which is one of important requirements for electronic marketplaces to offer similar privacy as current marketplace. It would be unsatisfactory for the subscriber to reveal his/her identity to purchase multimedia contents. In this paper we propose an anonymous broadcast encryption scheme, where a user can subscribe anonymously, but anonymity control is provided, i.e., a data supplier can trace traitors. Our scheme is constructed based on an asymmetric public-key traitor tracing scheme with one trustee.
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