Patent ID: 7889868

Claim:
A method for distributing quantum cryptographic keys, comprising: receiving, at an intermediate key forwarding device, a first quantum signal from an initial quantum key generating transmitter; corresponding, by the intermediate key forwarding device, with the initial quantum key generating transmitter to generate a first quantum key; transmitting, by the intermediate key forwarding device, a second quantum signal to a recipient quantum key generating transmitter; corresponding, by the intermediate key forwarding device, with the recipient quantum key generating receiver to generate a second quantum key; encoding, by the intermediate key forwarding device, the first quantum key using the second quantum key; and transmitting, by the intermediate key forwarding device, the encoded first quantum key to the recipient quantum key generating receiver, wherein receiving the first quantum signal and corresponding with the initial quantum key generating transmitter each occur via a single combined channel that includes the first quantum signal and a public data signal alternating in a time shared manner, and wherein receiving the first quantum signal and corresponding with the initial quantum key generating transmitter further comprises: splitting the single combined channel signals into a first split signal and a second split signal; applying a low attenuation to the first split signal when the first split signal includes the first quantum signal; applying a high attenuation to the first split signal when the second split signal includes the public data signal; receiving the first split signal at an intermediate quantum key generating receiver; receiving the second split signal at an intermediate quantum key public data receiver; applying a high attenuation prior to splitting the single combined channel signals when the first split signal includes the first quantum signal; and applying a low attenuation prior to splitting the signal combined channel when the first split signal includes the first public data signal.