Abstract
An online buyer of multimedia content does not want to reveal his identity or his choice of multimedia content whereas the seller or owner of the content does not want the buyer to further distribute the content illegally. To address these issues we present a new private anonymous fingerprinting protocol. It is based on superposed sending for communication security, group signature for anonymity and traceability and single database private information retrieval (PIR) to allow the user to get an element of the database without giving any information about the acquired element. In the presence of a semi-honest model, the protocol is implemented using a blind, wavelet based color image watermarking scheme. The main advantage of the proposed protocol is that both the user identity and the acquired database element are unknown to any third party and in the case of piracy, the pirate can be identified using the group signature scheme. The robustness of the watermarking scheme against Additive White Gaussian Noise is also shown.