Information Hinding Based on GSM Full Rate Speech Coding

A steganographic method is proposed to embed secret data in GSM full rate transcoding bit stream. Depending on the unequal importance with respect to speech subjective quality of encoded parameters and their individual bits, appropriate bits, which have relatively low importance for the quality of host speech, are chosen to embed secret data. The secret information can be anything such as another compressed speech or a text. The mean opinion score (MOS) of the stego-speech is around 3.5, satisfying the requirement of communication quality