On Information Embedding When Watermarks and Covertexts are Correlated

In this correspondence, a new digital watermarking scenario is studied, where watermarks and covertexts are correlated with each other. A necessary and sufficient condition is derived under which a watermark is first embedded, and can later be recovered with high probability at the output of a public watermark decoder after the watermarked signal is disturbed by a fixed memoryless attack channel. Interestingly, the condition also implies that the Shannon separation theorem does not hold in this scenario.