Method and apparatus for preventing piracy of digital content

摘要

A secure cryptographic rights unit for cryptographically regulating access to digital content includes an interface control processor and a specialized cryptographic unit that protects access to a memory. Rights keys, which allow access to content, are added by the cryptographic unit by transforming data received from the control processor and storing the result in the protected memory. The cryptographic unit then produces content decryption keys by using stored rights keys to transform other data received from the control processor. Because the control processor does not have the ability to directly access the protected memory, the security can remain effective even if the control processor is compromised. To prevent reverse engineering of the cryptographic transformations, the invention provides for an algorithm generator that uses random sources to produce algorithm definitions in machine-readable form. Because the generator itself does not contain any secrets, it can be submitted for open review.