PriWhisper+: An Enhanced Acoustic Short-Range Communication System for Smartphones

Abstract

The recent proliferation of Internet of Things (IoT) device coupled with the demand for an inexpensive way of transmitting data has been the primary factors behind the popularity of the short-range acoustic communication. It enables a seamless transfer of digital information via soundwaves, using device’s loudspeaker and microphone only and the whole interaction takes place without the need for network connection. Due to the limited computational power of the IoT device, the short-range acoustic communication system has adopted the friendly jamming technology to save energy. However, the security of the friendly jamming technology in mobile applications has not been thoroughly studied. When propagating sound in public, the soundwaves are subject to eavesdropping by nature. In particular, the friendly jamming technology is vulnerable to the separation attacks which can separate data signals from mixed signals. In this paper, we propose PriWhisper+—a secure acoustic short-range communication system between IoT devices. We analyze the security of PriWhisper+ via information theory and propose physical security enhancement mechanisms for acoustic communication by combining device mobility with secret sharing scheme. We then design a secure data communication scheme that transmits data in acoustic signals. This scheme can be applied in many security-sensitive situations, such as device pairing, contactless payments, and privacy data sharing. At last, we evaluate the performance of our proposed PriWhisper+ by extensive experiments on Android smartphones. The results of the experiment show that the PriWhisper+ can protect the data confidentiality within thirty centimeters of communication range.