Practical Secret-Key Generation by Full-Duplex Nodes with Residual Self-Interference

In the upcoming Internet of Things (IoT), encryption of confidential data by secret keys is vital. Secret-key generation from reciprocal wireless channels has received much attention in the research community in recent time. However, most implementations were restricted to half-duplex channel probing only. Communication setups with full-duplex (FD) capability enable new prospects for secret-key generation, since the inherent superposition of FD signals renders the acquisition of secret information more difficult for an eavesdropper. In this work, we demonstrate a practical testbed with FD capability in order to evaluate its advantages for secret-key agreement. We quantify the performance by computing correlation coefficients and mutual information of all channel estimates. Our work provides new insights into the opportunity of downgrading the capabilities of eavesdroppers by using full-duplex nodes.