A Reciprocity Approach for Shared Secret Key Generation Extracted from Received Signal Strength in The Wireless Networks

Shared secret key generation extracted from wireless channel information and parameters in the wireless PHY-layer is one of solutions to substitute key management mechanism in the conventional security schemes such as symmetric and asymmetric cryptosystems. However, the similarity of the decided shared key between two legitimated users should be confirmed as soon as possible. Hence, the key can be used for cryptosystem successfully. In this paper, we propose an investigation of shared secret key generation scheme by extracting secret key bits stream from received signal strength (RSS) in the wireless communication between these two users. We adopted Kalman Filter method in the randomness extraction phase to obtain a better reciprocity of bits stream. Meanwhile, experimental results showed the practicality of the proposed scheme compared with similar existing schemes in term of secret key bits stream with better reciprocity, low key disagreement rate (KDR), and proper key generation rate (KGR). In addition, the randomness of the key passes the National Institute of Standard and Technology (NIST) statistical test suite as well.