Random number generation from multipath propagation: MIMO-based encryption key establishment

This paper discusses the concept of using the physics associated with multipath propagation and multiple antennas to establish secure encryption keys between two wireless nodes in a network. The presentation includes a proposed algorithm for generating uncorrelated keys despite the fact that the random numbers generated by the propagation channel exhibit spatial and temporal correlation. It further briefly discusses some of the measures that must be taken to make the algorithm implementation practical as well as the theoretically-achievable performance of the algorithm. Simulation results using a physical path-based time-variant MIMO model demonstrate that the length of the established key grows as antennas are added. Furthermore, for high SNR environments, the algorithm is able to achieve a key length versus SNR curve whose slope matches that of the theoretically achievable bound.