Abstract   In the current paper, we have presented a novel wat ermarking scheme with making watermark as robust wh ile keeping the image fragile using Residue Number Syst em (RNS) and Chaos. Residues of the image are made to keep it secure since, their sensitive to change is high. Only Regi on Of Interest (ROI) part of the image is residued. In making residues of ROI, some residues exceed bit size eight so, these resid ues are converted to eight bits by applying some tr ick. Two watermarks are embedded in two stages; one to achieve robustness u sing Spread Spectrum (SS) technique and other to achieve fragility of image by calculating the digest of image. In the fi rst stage, spreaded watermark is embedded in Region Of Non0Interest (RONI) pixels using the chaotic key and in the seco nd stage, hash calculated from the first stage is again embedded in RONI pixels based on the chaotic key . Moreover, the original image is not needed at recei ver end, which makes the proposed scheme blind.

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