An efficient buyer-seller watermarking protocol based on composite signal representation

Buyer-seller watermarking protocols integrate watermarking tech-niques with cryptography, for copyright protection, piracy tracing, and privacy protection. In this paper, we propose an efficient buyer-seller watermarking protocol based on homomorphic public-key cryptosystem and composite signal representation in the encrypted domain. A recently proposed composite signal representation al-lows us to reduce both the computational overhead and the large communication bandwidth which are due to the use of homomor-phic public-key encryption schemes. Both complexity analysis and simulation results confirm the efficiency of the proposed solution, suggesting that this technique can be successfully used in practical applications.