Physical layer key generation against MIMO eavesdropper by exploiting full-duplex technology

Generating a shared secret key from physical layer is an interesting topic with practical value. Inspired by the encouraging progress on full-duplex radio, a novel mechanism aiming at high and steady key generation rate with low cost is proposed in this paper. Legitimate users simultaneously send random bit sequences to actively interfere with each other. They extract those mutually jammed bits to form a secret key. A special digital modulation scheme, called Random Manchester coding is proposed. The proposed scheme achieves three goals. The first and the most important one is to prevent a MIMO eavesdropper from separating the superposed signal; the second one is to detect denial of service and key compromise attack to defend against an active attacker; the third one is to achieve design goal on low power radiation, computational complexity and memory cost. Theoretical analysis, numerical simulations and concept-proof experiments validate the effectiveness of our proposed scheme. Our solution is promising to facilitate key generation applications of nearby wireless devices such as ubiquitous smartphones, wearable devices.