Patent ID: 8503673

Claim:
A method for generating a related pair of encryption keys at a first device and at a second device, the method comprising: providing a first device configured to transmit and receive a radio signal over one or more channels, said first device being configured to calculate an impulse response based on a received radio signal, and further configured to quantize an impulse response; providing a second device configured to transmit and receive a radio signal over said one or more channels, said second device being configured to calculate an impulse response based on a received radio signal, and further configured to quantize an impulse response; causing said second device to send a first radio signal through said one or more channels to said first device; receiving said first radio signal at said first device, said first received signal having a first temporal link signature; causing said first device to calculate a first impulse response based on said first temporal link signature; causing said first device to quantize said first impulse response to generate a first key for modification of radio signals; causing said first device to send a second radio signal through said one or more channels to said second device; receiving said second radio signal at said second device, said second received radio signal having a second temporal link signature; causing said second device to calculate a second impulse response based on said second temporal link signature; causing said second device to quantize said second impulse response to generate a second key substantially identical to said first key subsequent to a movement of said first device relative to said second device, causing said second device to send a third radio signal through a second one or more channels; receiving said third radio signal at said first device, said third received radio signal having a third temporal link signature; causing said first device to calculate a third impulse response based on said third temporal link signature; causing said first device to quantize said third impulse response to generate a third key; causing said first device to combine said first key and said third key to generate a fourth key for modification of radio signals; subsequent to the movement of said first device relative to said second device, causing said first device to send a fourth radio signal through said second one or more radio channels; receiving said fourth radio signal at said second device, said received radio signal having a fourth temporal link signature; causing said second device to calculate a fourth impulse response based on said fourth temporal link signature; causing said second device to quantize said fourth impulse response to generate a fifth key; and causing said second device to combine said second key and said fifth key to generate a sixth key substantially identical to said fourth key for modification of radio signals.