Method for tracing traitors and preventing piracy of digital content in a broadcast encryption system

摘要

A system, method, and computer program product to prepare files for transmission in a broadcast encryption system to prevent piracy and enable traitor tracing. Typically, each file in a group of original files is modified to include variations of critical file segments. A file identifier denotes which set of variations corresponds to which file. The group of files is then broadcast with individualized codes that enable particular authorized receivers to properly process the modified files. The modifications in a pirated version of a file can identify which traitorous receivers contributed to its piracy; such receivers may be subject to legal action and selective cryptographic revocation. The invention minimizes the likelihood of falsely concluding an innocent receiver is traitorous yet can identify large groups of colluding attackers with only a small increase in broadcast bandwidth overhead.