Studying Audio Capacity as Carrier of Secret Images in Steganographic System

Abstract

Steganography art is a technique for hiding information where the unsuspicious cover signal carries the secret information. Good steganography technique must include the important criterions e.g. robustness, security, imperceptibility and capacity. Improving each one of these criterions will effect the others, because these criterions are overlapped. In this work, a good high capacity audio steganography safely method has been proposed based on LSB random replacing of encrypted cover with encrypted message bits at random positions. The research also included a study for the audio file, speech or music, by safely manner to carrying secret images, so it is difficult for unauthorized persons to the suspect presence of the hidden image. Calculations of SNR, SNR segmental, SNR spectral, MSE and correlation show that, audio music cover file (2channales) is the safest as a carrier with replace the 9 number of LSB without noticeable noise. The capacity of the audio file that can be safely exploited is up to 28% of the total size of the music audio cover; this fact can be noticer from the values of measures of SNR, SNR_Seg and SNR_Spec (32, 28 and 31 dB). For speech cover audio the replacing LSB is safely uses LSB bits number 6, where the hiding capacity reach up to 37 % of size speech cover audio at 37, 36 and 39 dB for three type's measures of SNR. Correlation of cover samples was not affected as a result of hiding secret image, where its value is up to 0.99 for all hiding operations.