An Investigation of Secret Key Generation for Physical Layer Security Using Wavelet Packets

This work investigates the effectiveness of wavelet packets in dynamic secret key generation (DSKG) for physical layer security (PLS). Preprocessing channel coefficients before quantization is highly essential in DSKG, as noisy measurements on direct quantization produces distinct keys at the transmitter and receiver. Secret keys generated will be having high key disagreement. The performance of different wavelets namely, Daubechies, Symlet and Coiflet, of orders 3 and 5, are studied using Spearman correlation coefficient, bit disagreement rate and NIST randomness tests. NIST tests are evaluated for different bit sequence lengths and as an outcome of the experiment, the best performing wavelet is identified. Further, the proposed work is compared with an existing scheme. It is inferred that, along with maintaining higher correlation coefficient, wavelet packet based DSKG scheme ensures an enhancement in PLS.