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Distribution channels such as digital music downloads, video-on-demand, and multimedia social networks pose new challenges to the design of content protection measures aimed at preventing copyright violations. Digital watermarking has been proposed as a possible brick of such protection systems. However, application of watermarking for multimedia content protection in realistic scenarios poses several security issues. Secure signal processing, by which name we indicate a set of techniques able to process sensitive signals that have been obfuscated either by encryption or by other privacy-preserving primitives, may offer valuable solutions to the aforementioned issues. More specifically, the adoption of efficient methods for watermark embedding or detection on data that have been secured in some way, which we name in short secure watermarking, provides an elegant way to solve the security concerns of applications. A digital watermarking technique is used to generate meaningful shares. The secret image shares are watermarked with different cover images and are transmitted. At the receiving side the cover images are extracted from the shares and stacked one by one which reveals the secret image progressively. Digital watermarking using visual cryptography provides improved security for encrypting secret images.