Lossless Data Hiding For Image Using Reversible Contrast Mapping (RCM)

Data hiding is still an important research topic due to the design complexities involved. Steganography is the technique of hiding confidential information within any media. Steganography is often confused with cryptography because the two are similar in the way that they both are used to protect confidential information. But because of loss in any quality of original image, the authors have proposed a Reversible Contrast Mapping (RCM), a simple integer transform that applies to pairs of pixels. For some pairs of pixels, RCM is invertible, even if the least significant bits (LSB) of the transformed pixels are lost. The embedded information bit-rates of the proposed spatial domain reversible watermarking scheme are close to the highest bit-rates reported so far. The scheme does not need additional data compression, and, in terms of mathematical complexity, it appears to be the lowest complexity one proposed up to now. A very fast lookup table implementation is proposed. Robustness against cropping can be ensured as well.