Science and Development Network (SciDev.Net)
This paper presents a technique for secret communication using cryptography and steganography. The cryptographic algorithm is a block cipher with a block length of 128 bits and key length of 256 bits. The secret message is encrypted by this block cipher. Two cipher text bits are to be embedded in each pixel of the image. Each pixel is 8 bits. The embedding locations in a pixel are: 6th and 7th bit locations or 7th and 6th bit locations or 7th and 8th bit locations or 8th and 7th bit locations depending upon the cipher text bits. The 8th bit means the Least Significant Bit (LSB). As the embedding locations are decided at the run time of the algorithm, so it is called as dynamic steganography.