A FRAGILE WATERMARKING ALGORITHM FOR IMAGE TAMPERING DETECTION AND CONTENT RECOVERY BASED ON CHAOS

Abstract

With the exponential advancement in networking technologies and multimedia tools, image authentication has become a major challenge. This paper presents a new fragile watermarking method for tampering detection and content recovery. Using 2 x 2 sized image blocks, eight bit watermark is derived by encoding the low frequency component of the discrete cosine transform (DCT) coefficients of the block. The watermark is embedded in the two leastsignificant bit planes of the cover image. A non-linear chaotic sequence based on Arnold cat map isused for block mapping. Experimental results indicate that the proposed algorithm performs better as compared to the existing state of the art methods.