Secret-Key-Agreement Advantage Distillation With Quantization Correction

We consider a physical layer-based secret-keyagreement (SKA) scenario where Alice and Bob aim at extracting a common bit sequence, which should remain secret to Eve, by quantizing a random number obtained from measurements of their communication channel. We propose an asymmetric advantage distillation protocol where i) Alice quantizes her measurement and sends partial information on it over an authenticated public side channel, and ii) Bob (and Eve) quantizes his measurement by exploiting the partial information. The partial information on the position of the measurement in the quantization interval allows Bob to obtain a quantized value closer to that of Alice. Such strategies are shown to increase the lower bound of the secret key rate.