Wireless channel-based ciphering key generation: effect of aging and treatment

Key generation for data cryptography is vital in wireless communications security. This key must be generated in a random way so that can not be regenerated
by a third party other than the intended receiver. The random nature of the
wireless channel is utilized to generate the encryption key. However, the randomness of wireless channels deteriorated over time due to channel aging which
casing security threats, particularly for spatially correlated channels. In this paper, the effect of channel aging on the ciphering key generations is addressed.
A proposed method to randomize the encryption key each coherence time is developed which decreases the correlation between keys generated at consecutive
coherence times. When compared to the conventional method, the randomness
improvement is significant at each time interval. The simulation results show
that the proposed method improves the randomness of the encrypting keys.