Renewable traitor tracing

The present invention provides a method performed on a computer of preventing re-use of compromised keys in a broadcast encryption system. In an exemplary embodiment, the method includes (1) incorporating a particular set of Sequence Keys assigned by a license agency into individual receivers, (2) assigning a Sequence Key Block (SKB) by the license agency to at least one distributed protected file, (3) performing incremental cryptographic testing by the individual receivers to determine if a selected Sequence Key from the set of Sequence Keys is compromised, (4) if the selected Sequence Key is not compromised, decrypting the file, and (5) if the selected Sequence Key is compromised and if a subsequent Sequence Key from the set of Sequence Keys is available, selecting the subsequent Sequence Key.