Exploiting Security Holes in Lattice Data Hiding

This paper presents a security analysis for data hiding methods based on nested lattice codes, extending the analysis provided by previous works. The security is quantified in an information-theoretic sense by means of the information leakage between the watermarked signals seen by the attacker and the secret key used in the embedding process. The theoretical analysis accomplished in the first part of the paper addresses important issues such as the possibility of achieving perfect secrecy and the impact of the embedding rate and channel coding in the security level. In the second part, a practical algorithm for estimating the secret key is proposed, and the information extracted is used for implementing a reversibility attack on real images.