An improved QIM based anti-collusion fingerprinting scheme

Digital fingerprinting is a technique by embedding a unique identifying signal which corresponds to the user´s identity in each legally distributed copy. A digital fingerprinting system may suffer from the collusion attacks from a group of users. Quantization Index Modulation (QIM) is an important embedding technique. In QIM, quantization step size has a marked influence on the detection performance of fingerprinting system. Higher the value of quantization step size is, worse the detection performance is. Therefore, we propose an improved QIM based fingerprinting scheme by adding a random dither signal to the host signal to enhance the collusion resistance of fingerprinting system. Simulation results show that the improved fingerprinting system has better collusion resistance than traditional QIM based fingerprinting system.