Research On Group Secret Key Generation Based On Wireless Channel Characteristics

With the development of Internet of Vehicles and mobile ad hoc networks,multi-node wireless communication systems have been widely used.Different from traditional key generation mechanisms,physical layer key generation mainly uses the reciprocity,uniqueness and time-varying of wireless channels to generate keys.It can achieve information theoretic-security and lower computational complexity,thus is more suitable for resource-constrained networks.Compared with point-to-point pairwise key generation scheme,group key generation scheme faces more challenges due to the complexity of the group network topology.Therefore,physical layer group key generation scheme with respect to ring topology and mesh topology is studied in this thesis.First of all,we analyze the existing group channel probing scheme and point out the problem that the available probing time for each node decreases with the increase of group size.To solve the problem,a two-step channel probing scheme based on dual antennas is designed.The simulation results show that the proposed scheme can bring a higher group key rate with total power constraint when the group size becomes large.Secondly,we analyze the advantages and disadvantages of the existing group key distribution scheme,and propose "one-time-pad"two-way two-segment transmission scheme.The scheme has higher transmission efficiency and can achieve the security capacity.Finally,we analyze the relationship between group key rate and pairwise key rate.It is pointed out that the generated pairwise key cannot be fully utilized unless the pairwise key rate is less than or equal to the"initial" group key rate.Based on the relationship,we design a power allocation scheme by exploiting particle swarm optimization algorithm.The simulation results demonstrate the effectiveness of the proposed scheme.