关键词: 声信道, 物理隔离, 智能终端设备, 隐蔽信息, 信息传输

Abstract: In this paper we introduce a transmission technology of covert information using acoustic channel. As one of key covert communication technologies, it has been attracting widespread attention and interest in the study field of physical security. This technology can achieve the transmission of hidden information between smart terminal devices, such as smart phones and personal computers. The secret data was transformed into a sound wave (frequency ranging from 15kHz to 20kHz) and then sent out by speakers from transmitting end. At the receiving end, the sound wave was recorded by microphones and decoded. Compared with other close range communication modes, this technology has obvious advantage, not only can be implemented simply with low cost as long as the transmitter and the receiver are broadcast and recording equipment can be achieved,but also assure that the covert transmission of information in the hidden voice channel without detecting the existence of secret information by the third party

Key words: acoustic channel, physical separation, terminal device, covert communication, information transmission