Asymmetric image watermarking based on reversible chaotic maps

Watermarking is used as a way of hiding information in digital media to allow copyright protection. Until today, most work has been symmetric, with the risk of revealing the hidden information. The present paper presents an asymmetric watermarking approach, which generates keys for embedding and detecting the watermark using partial iterations of a reversible chaotic map. It uses a novel method, which embeds twin watermarks to achieve copyright identification with public information. Illegal users cannot perceive and break the watermark because of the private embedding key, and the contents of the watermark are not revealed. The experimental results show that the proposed scheme maintains proper robustness against several incidental attacks, including JPEG compression, additive noise, medium filtering and rescaling.