The buyer-seller watermarking protocol enables a seller to successfully identify a traitor from a pirated copy, while preventing the seller from framing an innocent buyer. Based on finite field theory and the homomorphic property of public key cryptosystems such as RSA, several buyer-seller watermarking protocols (N. Memon and P. W. Wong (2001) and C.-L. Lei et al. (2004)) have been proposed previously. However, those protocols require not only large computational power but also substantial network bandwidth. In this paper, we introduce a new buyer-seller protocol that overcomes those weaknesses by managing the watermarks. Compared with the earlier protocols, ours is n times faster in terms of computation, where n is the number of watermark elements, while incurring only O(1/lN) times communication overhead given the finite field parameter lN. In addition, the quality of the watermarked image generated with our method is better, using the same watermark strength.
- Buyer seller protocol,
- Buyer-seller watermarking,
- Communication overheads,
- Computational power,
- Finite field theory,
- Finite fields,
- Homomorphic property,
- Network bandwidth,
- Public key cryptosystems,
- Watermarked images
Available at: http://works.bepress.com/hweehwa-pang/5/