Using Covering-Stego Image Block to Enhance the Performance of CLSB Method of Message Steganography

A new efficient method of secret message steganography will be introduced; the method will use an image-block as a covering-stego media, this block will be secret and it will be determined by the selected private key. The image-block will be substituted before message hiding-extracting, and it will be substituted back after message hiding. The method will provide a high security level to protect the hidden message, the private key will have a length of 384 bits, this length will be good enough to provide a huge key space capable to resist hacking attacks, the extracted message will be very sensitive to the selected values of the private, any changes in the private key in the extraction phase will be considered as a hacking attempt by producing a damaged unreadable message. The private key will be used to select the secret image-block and to generate two indices keys, which are required to apply image-block rows and column substitution. The indices key will be obtained by running two simple chaotic logistic map models. The proposed method will use inconsecutive and separate covering-stego bytes and the process of message bits hiding will be applied in batch way by performing a single replacement operation. The proposed method will be implemented using various messages and various covering images, the obtained results will be used to prove the enhancements provided by this method in the quality and speed of message steganography.