Alpha channel-Based Indicator For Robustness Forward/Backward LSB Steganography

Steganography is important technique for protecting confidential media (text, image, audio, etc.) by embedding it on another media object calling a cover or carrier, subject to no one can discovered. There is a conflict between the developers of Steganography and Steganalysis (detecting hidden messages), Therefore, there must be a rapid development in the creation of complex algorithms to hide information in a way that is difficult to analyze and access. This research introduces a new image steganography technique, Alpha Channel Based Steganography, that differently others algorithms by hiding secret information depending on Alpha Channel where using RGB channels as search space and alpha channel as an indicator for hiding and retrieving confidential data. two least significance bits in alpha channel using to indicate which RGB channel have the secret bit and other two to indicate the rounds number and type (forward and backward search) until secret message end. Using Alpha Channel in the introduced algorithm increase robustness against Steganalysis. Moreover, the capacity of hidden information has also increased due to the quadrupling of the search field in one image, where no visual attack can detect stego image even with maximum hiding capacity. After testing, evaluating and comparing with other algorithms, the proposed algorithm scoring 0% in MSE test, infinite in PSNR test, and 1 for SSIM test, the result of testing indicate that the proposed algorithm achieves the best results according to steganography aspects: imperceptibility, capacity and robustness.