Anti-collusion fingerprinting with scalar Costa scheme (SCS) and colluder weight recovery

An anti-collusion fingerprinting system is developed to protect media files against time-varying collusion attacks based on the scalar Costa scheme (SCS) and colluder weight recovery. We treat the host signal as a parallel Gaussian channel and fingerprints as transmitted user signals. We decompose the Gaussian channel into multiple independent subchannels, and assign different user messages to different subchannels. Then, colluder weights in collusion attacks can be estimated using pilot symbols at the decoder, and all weights can be estimated and compensated. As a result, the decoding region on the parametric space can be recovered as an original format. It is shown by experimental results that the proposed fingerprinting system has excellent performance in colluder detection.