A two-stage traitor tracing scheme for hierarchical fingerprints

Abstract

The multimedia traitor tracing field involves the embedding of a collusion secure fingerprint in the host signal to retrieve and prevent any multimedia content fraud. Trendy work aims at providing a tracing system which offers a good protection of the digital content and an efficient tracing process. These challenges depend on reducing the length of the embedded fingerprint and the complexity of the accusation process. Furthermore, addressing these issues becomes more and more relevant in media distribution applications involving an important number of users. In this paper, we propose a secure fingerprinting system based on a two-stage tracing strategy which combines two probabilistic tracing codes: Boneh Shaw with replication scheme and Tardos codes. This strategy is applied to a multilevel hierarchical fingerprint which is then embedded using a DCT-based audio watermarking technique. By taking the advantage of grouping users and applying a weight-based tracing process, the proposed fingerprinting system offers to reduce efficiently the computational costs of the tracing time. It has also a good robustness to different types of attacks. We have carried out different tests to evaluate the performance of the system in terms of robustness and imperceptibility. The experimental results show that the proposed fingerprinting system provides a suitable solution to the the infringement copyright problem in multimedia distribution platforms by reducing significantly the users’ retrieval space and performing good detection results in a reduced time.