Patent ID: 8959348
Filing Date: 2015-02-17
Classification: H04L

Abstract:
1. A method for establishing a symmetric encryption key between a first device and a second device, the method comprising: (a) transmitting a first carrier wave signal generated using circuitry at the first device, from the first device to the second device, the first carrier wave signal being characterized by a first center frequency and transmitted for a first predetermined time duration; (b) receiving the first carrier wave signal by the second device, the second device being configured to sample the first carrier wave signal for the first predetermined time duration at a second sampling rate to obtain a first phase difference value, the second sampling rate being characterized by a second center frequency generated by the second device substantially equal to the first center frequency; (c) transmitting a second carrier wave signal generated using circuitry at the second device, from the second device to the first device within a predetermined second time duration after receiving the first carrier wave signal, the second carrier wave signal being characterized by the second center frequency and transmitted for the first predetermined time duration; (d) receiving the second carrier wave signal by the first device, the first device being configured to sample the second carrier wave signal for the first predetermined time duration at a first sampling rate to obtain a second phase difference value, the first sampling rate being characterized by the first center frequency; and (e) establishing a first symmetric encryption key based on the first phase difference value and a second symmetric encryption key based on the second phase difference value.