Waldemar Berchtold

Learn More
To trace back copyright infringements, digital transaction watermarking today is a widely accepted method. Here, copies of a single work are individualized by embedding userspecific watermark messages. However, transaction watermarking is vulnerable to collusion attacks, where multiple individualized copies of one work are compared and/or combined to attack(More)
Digital transaction watermarking today is a widely accepted mechanism in multimedia security. Here, copies of one work are distributed with individual markings. One major threat on transaction watermarking are collusion attacks. Here multiple individualized copies of the work are mixed in order to create a counterfeited or undetectable watermark. One(More)
Collusion attacks on watermarked media copies are commonly countered by probabilistically generated fingerprinting codes and appropriate tracing algorithms. The latter calculates accusation scores representing the suspiciousness of the fingerprints. In a 'detect many' scenario a threshold decides which scores are associated to the colluders. This work(More)