KEY BASED STEGANOGRAPHY IN A GRAY LEVEL IMAGE INVOLVINGPERMUTATION AND MODULAR ARITHMETIC ADDITION

[摘要] In this investigation, we have developed a procedure for the steganography of a plaintext in an image. The process involved in this is fully based upon a key. In this analysis, firstly, the plaintext is modified by permuting with the key and by carrying out the modular arithmetic addition with the key. The transformed plaintext obtained in the above manner is concealed in the image by following a procedure which is based upon the key. Here the image is divided into 256 blocks and modified plaintext containing 256 characters is hidden in 4 blocks. The strength of this steganography is found to be quite significant.

[关键词] steganography;plaintext;permutation;modified plaintext;key;modular arithmetic addition