Image security using DES and RNS with reversible watermarking

In this modern world of Internet and with the development of digital communication and multimedia application, image security has become an important concern in storage and communication. A cryptography technique provides good strength for securing and protecting images essentially in the fields as medical, law enforcement and military. Reversible watermarking provides authentication, in which original image and watermark gets recovered. In this paper, Initially, secrete image is passed through S-DES (Simple-Data Encryption Standard) using a key image, then this encrypted image is watermarked using a watermark image and a position matrix, this watermarked image is passed through RNS (Residue Number System) and finally we get our DES watermarked RNS encoded image. For decoding, we have to go in reverse order, i.e. initially reverse RNS (CRT, Chinese Remainder Theorem) followed by watermark and S-DES encoded image extraction and hence our secrete image back.