A Lightweight Buyer-Seller Watermarking Protocol

Abstract EN

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.