The invention relates to a speech 
information hiding secret communication 
system which organically integrates techniques, such as 
information hiding, passwords, communication, and the like. In the invention, MELP2.4KBps secret speech is hidden in the public speech of G.721, G.728, 
GSM and G.729 of a code-excited 
linear prediction code by connecting a public 
telephone network PSTN, mobile communication 
GSM / CDMA, videoconferences and a VoIP network and utilizing a speech 
information hiding and 
extraction algorithm, and a private channel is established in a public 
communication channel to carry out the real-time secret communication of secret speech information. The 
system adopts an embedded type technique based on DSP, and designs corresponding functional modules, such as 
speech coding and decoding, speech 
encryption and decryption, speech information hiding and extraction, and the like. Under the condition that a certain communication rate and a certain 
speech quality are ensured, secret speech real-time communication is carried out on various public channels, and the 
communication quality reaches the requirement of a communication standard.