A New Soft Decision Tracing Algorithm for Binary Fingerprinting Codes
The performance of fingerprinting codes has been studied under the well-known marking assumption. In a realistic environment, however, a pirated copy will be distorted by an additional attack. Under the assumption that the distortion is modeled as AWGN, a soft decision method for a tracing algorithm has been proposed and the traceability has been experimentally evaluated. However, the previous soft decision method works directly with a received signal without considering the communication theory. In this study, we calculate the likelihood of received signal considering a posterior probability, and propose a soft decision tracing algorithm considering the characteristic of Gaussian channel. For the estimation of channel, we employ the expectation-maximization algorithm by giving constraints under the possible collusion strategies. We also propose an equalizer to give a proper weighting parameter for calculating a correlation score.
KeywordsCentral Limit Theorem Gaussian Mixture Model Correlation Score Hard Decision Gaussian Channel
Unable to display preview. Download preview PDF.
- 4.Furon, T., Preire, L.P.: EM decoding of Tardos traitor tracing codes. ACM Multimedia and Security, 99–106 (2009)Google Scholar
- 9.Nuida, K.: Making collusion-secure codes (more) robust against bit erasure. eprint 549, 2009 (2009)Google Scholar
- 12.Simone, A., Skoric, B.: Accusation probabilities in Tardos codes: the Gaussian approximation is better than we thought. Cryptology ePrint Archive, Report 2010/472 (2010), http://eprint.iacr.org/
- 14.Wu, M., Trappe, W., Wang, Z.J., Liu, K.J.R.: Collusion resistant fingerprinting for multimedia. IEEE Signal Processing Mag., 15–27 (2004)Google Scholar