A Novel Group Secret Key Generation: Performance Analysis and Secrecy Improvement

Mutual random phase injection can be considered an appropriate solution for tackling the low key generation rate issue in physical layer key generation schemes. In this paper, the confidentiality of a phase-based group secret key generation scheme has been analyzed by employing a geometric secrecy approach in a static environment. Accordingly, we exploit this approach to achieve some common randomness quantities in our group model. For this purpose, the process of key generation is defined for a star topology. Next, both vulnerability and secrecy regions are identified. To address the challenge of security vulnerability in non-proximity areas due to the spatial correlation in static environments with dominant line-of-sight (LoS), multiple carrier frequencies have been employed at the channel probing stage to enhance the secrecy regions. Finally, the key error probability is provided not only to establish an appropriate evaluation of the quality of the generated keys but also to show the efficiency of our proposed scheme in comparison with previous works.