Subcarrier Number and Indices-Based KeyGeneration for Future Wireless Networks

Physical layer key generation from the wireless channel is an emerging area of interest to provide confidentiality and authentication. One of the main challenges in this domain is to increase the length of the secret key while maintaining its randomness and uniformity. In this work, new dimensions for wireless channel-based key generation are proposed for orthogonal frequency division multiplexing (OFDM) systems. The novel perspective of the proposed work lies in the generation of key bits not only from the magnitudes of OFDM subchannels as it has conventionally been done but also from the number and positions of those subchannels whose channel gains are above the mean of the respective subblock. The effectiveness of the proposed algorithms is evaluated in terms of key generation rate and key mismatch rate. Additionally, a statistical test suite offered by the National Institute of Standards and Technology is used to evaluate the randomness of the generated key bits. It is shown in the simulation results that the involvement of the proposed dimensions can double the key generation rate compared to conventional algorithms.