Research On Quantization Index Modulation Based Anti-Collusion Fingerprinting Technology

With the rapid development of network and multimedia processing techniques, digital products were spread widely. At the same time, many chances have been brought to piracy so that copyright protection of multimedia was growing more and more important. Digital fingerprinting is a copyright protection technology which embedded a unique fingerprinting into each user's copy by making use of redundancy of digital works. A cost-effective attack is the collusion attack to the digital fingerprinting system. For fingerprint embedding techniques, spread spectrum technique and quantization technique were employed widely. QIM (Quantization Index Modulation) is a typical application of quantization techniques.At present, the research about digital fingerprints mainly concentrated on fingerprinting codes how to resist the collusion attacks and embedded and performance evaluation of fingerprinting system was less. Therefore, we mainly focus on the collusion resistance performance of fingerprinting system.Firstly, the fundamental principle was generally summarized and the realizable scheme of various parts for digital fingerprinting system was introduced. Then we proposed the design and algorithm of QIM based fingerprinting scheme and analyzed the correlation of Gaussian fingerprinting system between the collusion resistance and the quantization step size through the simulation. At last, an improved QIM based fingerprinting scheme was proposed and the collusion resistance were evaluated,then we made a comparison and evaluation to the collusion resistance and embedding distortion between the two kinds of fingerprinting system.Simulation results and analysis show that 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. The collusion resistance of improved fingerprinting scheme has distinct enhancement because the fingerprinting signal is more continuous after adding a dither signal.