Secret sharing: using meaningful image shadows based on Gray code

Steganography, such as secret sharing, is an important technique to use for protecting transmitted confidential data from the attention of any adversaries. Gray code is a commonly encountered binary labeling that was proposed by Frank Gray of Bell Laboratories in 1940 to prevent errors when using pulse-code modulation to transmit signals. The main features of Gray code are its recursive construction method and the fact that any two adjacent codes change only one bit. According to our observations, the image pixel correction based on these features is suitable for application secret sharing without making significant changes to the pixel value. We designed a reversible secret sharing method using meaningful image shadows based on Gray code. Our design applies absolute moment block truncation coding (AMBTC) compression to reduce the transmission bit rate. The experimental results show that our scheme can achieve the adequate visual quality of shadow images with lower communication overhead, thus proving it practical for numerous applications.