An efficient fingerprinting scheme with symmetric and commutative encryption

Abstract

The illegal copying and redistribution of digital content is a crucial problem to distributors who electronically sell digital content. Fingerprinting scheme is a technique which supports the copyright protection to track redistributors of digital content using cryptographic techniques. Anonymous fingerprinting scheme prevents the content provider from framing the buyer by making the fingerprinted version known to the buyer only. In designing a fingerprinting scheme, it is important to make it more practical and efficient. In this paper, we proposed a fingerprinting protocol to address the problem using cryptographic technologies and watermarking scheme. The digital content is encrypted using symmetric encryption. And keys, which are used to decrypt encrypted digital content, are double locked by two encryption keys kept separately by the buyer and the content provider. In the protocol, the buyer only gets a few of keys and can decrypt a few of fingerprinted digital contents in a transaction and the content provider has no idea how the fingerprint is formed. This facilitates the authority to determine the unethical party in case of illegal distributions of digital contents. © Springer-Verlag Berlin Heidelberg 2005.