Four nodes (mobile) in a network where one node will be considered as a central node responsible for generating and distributing the secret key shares to the other nodes using Shamir secret sharing technique.
Implementation of physical layer key exchange technique to create a separate pair of secret key between the central node and each mobile node. This key will serve as a pre-shared key that can be used by the central node to distribute the key shares to the other nodes.
Method of generating the physical layer key between two mobile devices based on the Received Signal Strength Indicator
1. Exchanging probe packets between two mobile devices to measure the RSSI
a. Measurement of Received signal strength Indicator using Bluetooth interface - Exchange of L2CAP packets between two mobile devices to measure the RSSI of each received packet (Link layer can record the RSSI value of every received packet)
2. Pre-quantization interpolation step to reduce the probability of bit mismatch
3. Adaptive Secret Bit Generation quantization schemes - quantization of RSSI values by using threshold to obtain an initial key stream
4. Information reconciliation - correction of bit mismatch using cascade-based information reconciliation
5. Privacy Amplification by using hash functions
• Creation of a secret key by the central node and distribution of the shares using pre-shared physical layer key
Performance analysis of the key generation technique such as key generation rate, entropy, randomness etc (for both physical layer key and secret sharing technique)
calculating the computational, storage and communication complexity
please refer to the uploaded paper to get more details on physical layer key exchange technique