Section: Application Domains
Copy protection, copyright enforcement and traitor tracing
Data hiding has gained attention as a potential solution for a wide range of applications placing various constraints on the design of watermarking schemes in terms of embedding rate, robustness, invisibility, security, complexity. Here are two examples to illustrate this diversity. In copy protection, the watermark is just a flag warning compliant consumer electronic devices that a pirated piece of content is indeed a copyrighted content whose cryptographic protection has been broken. The priorities are a high invisibility, an excellent robustness, and a very low complexity at the watermark detector side. The security level must be fair, and the payload is reduced to its minimum (this is known as zero-bit watermarking scheme). In the fingerprinting (or traitor tracing) application, user identifying codes are embedded in the host signal to dissuade dishonest users to illegally give away the copyrighted contents they bought. The embedded data must be non perceptible not to spoil the entertainment of the content, and robust to a collusion attack where several dishonest users mix their copies in order to forge an untraceable content. This application requires a high embedding rate as anti-collusion codes are very long and a great robustness, however embedding and decoding can be done off-line affording for huge complexity.