Eliminating Privacy Amplification in Secret Key Generation from Wireless Channels

The inherent randomness of wireless radio channels can be employed to extract secrets, whenever the channel reciprocity holds. Privacy amplification is an ingredient step for removing the redundancy of key, of which, the mount of information leaked to potential eavesdroppers, is often difficult to determine. In this paper, we propose a secret-key generation scheme without privacy amplification, of which the disagreement of key is coordinated through the reconciliation of sample positions as did in the level-crossing scheme. Compared to the level-crossing scheme, the proposed approach accumulates the reliable samples and further employs multi-bit quantization for improving the rate of secret-key generation. The accumulated samples should be decorrelated for generating random keys. Through extensive simulations, we find that the Karhunen-Lo`eve transform for decorrelation is very sensitive in implementation.