In order to protect copyrighted material, codes may be embedded in the content or codes may be associated with the keys used to recover the content.
Codes can offer protection by providing some form of traceability for pirated data.
Several researchers have studied different notions of traceability and related concepts in recent years. All these concepts can be formulated as codes having certain combinatorial properties. In this paper, we study the relationships between the various notions, and we discuss equivalent formulations using structures such as perfect hash families. Back to the library's main page or to the list of 2000 .