Encryption Key Distribution System and Method

1. A Kirchhoff-Law-Johnson-(like)-Noise (KLJN) system for secure key distribution, comprising: a wired network; and a plurality of hosts connected to each other on the wired network, wherein each host is connected to every other host by a continuous wired path capable of transmitting electrical current, wherein each host of the plurality of hosts comprises a first resistor and is configured to produce a first-resistor enhanced Johnson noise voltage when the first resistor is connected to a voltage source, wherein each host of the plurality of hosts further comprises a second resistor and is further configured to produce a second-resistor enhanced Johnson noise voltage when the second resistor is connected to a voltage source, wherein the resistance value of the first resistor of each host is identical to that of all other hosts of the plurality of hosts, wherein the resistance value of the second resistor of each host is the identical to that of all other hosts of the plurality of hosts, and wherein the plurality of hosts comprises at least three hosts.

2. The system according to claim 1 , wherein each host further comprises a filter box.

3. The system according to claim 2 , wherein the filter box comprises: a first KLJN filter for KLJN key exchange; and a main signal filter for supplying a main signal of the network to the host having the filter box.

4. The system according to claim 3 , wherein the wired network is a smart power grid, and wherein the main signal filter is a power filter for supplying power to the host having the filter box.

5. The system according to claim 3 , wherein at least one of the first KLJN filter and the main signal filter is a low pass filter.

6. The system according to claim 3 , wherein the first KLJN filter is connected to the first and second resistors, such that the first KLJN filter is connected between all other hosts and the first and second resistors of the host having the filter box.

7. The system according to claim 6 , wherein each host comprises a third resistor, and wherein the main signal filter is connected to the third resistor of the host having the filter box such that the main signal filter is connected between all other hosts and the third resistor of the host having the filter box.

8. The system according to claim 6 , wherein the KLJN filter comprises a first sub-filter and a second sub-filter, wherein, when open, the first sub-filter permits a signal to pass through the KLJN filter without reaching the first and second resistors, wherein, when open, the second sub-filter permits a signal to reach the first and second resistors, wherein the KLJN filter is configured such that, in an inactive state, the first sub-filter is open to Johnson noise and the second sub-filter is closed to Johnson noise, and wherein the KLJN filter is configured such that, in an active state, the first sub-filter is closed to Johnson noise and the second sub-filter is open to Johnson noise.

9. The system according to claim 1 , wherein the wired network is an existing infrastructure network.

10. The system according to claim 1 , wherein the wired network is a smart power grid.

11. A Kirchhoff-Law-Johnson-(like)-Noise (KLJN) method for secure key distribution using a system, wherein the system comprises: a wired network; and a plurality of hosts connected to each other on the wired network, wherein each host is connected to every other host by a continuous wired path capable of transmitting electrical current, wherein each host of the plurality of hosts comprises a first resistor and a second resistor, wherein the resistance value of the first resistor of each host is identical to that of all other hosts of the plurality of hosts, wherein the resistance value of the second resistor of each host is the identical to that of all other hosts of the plurality of hosts, wherein the plurality of hosts comprises at least three hosts, wherein the method comprises: connecting, to a voltage source, exactly one of the first resistor or the second resistor of a first host of the plurality of hosts, thereby producing a first-host enhanced Johnson noise voltage, which is transmitted to a second host of the plurality of hosts; connecting, to a voltage source, exactly one of the first resistor or the second resistor of the second host, thereby producing a second-host enhanced Johnson noise voltage, which is transmitted to the first host; and connecting, to a voltage source, exactly one of the first resistor or the second resistor of a third host of the plurality of hosts, thereby producing a third-host enhanced Johnson noise voltage, which is transmitted to the first host.

12. The method according to claim 11 , wherein each host further comprises a filter box.

13. The method according to claim 12 , wherein the filter box comprises: a first KLJN filter for KLJN key exchange; and a main signal filter for supplying a main signal of the network to the host having the filter box.

14. The method according to claim 13 , wherein the wired network is a smart power grid, and wherein the main signal filter is a power filter for supplying power to the host having the filter box.

15. The method according to claim 13 , wherein at least one of the first KLJN filter and the main signal filter is a low pass filter.

16. The method according to claim 13 , wherein the first KLJN filter is connected to the first and second resistors, such that the first KLJN filter is connected between all other hosts and the first and second resistors of the host having the filter box.

17. The method according to claim 16 , wherein each host comprises a third resistor, and wherein the main signal filter is connected to the third resistor of the host having the filter box such that the main signal filter is connected between all other hosts and the third resistor of the host having the filter box.

18. The method according to claim 16 , wherein the KLJN filter comprises a first sub-filter and a second sub-filter, wherein, when open, the first sub-filter permits a signal to pass through the KLJN filter without reaching the first and second resistors, wherein, when open, the second sub-filter permits a signal to reach the first and second resistors, and wherein the method further comprises: placing the KLJN filter in an inactive state by opening the first sub-filter to Johnson noise and closing the second sub-filter to Johnson noise; and placing the wherein the KLJN filter is in an active state, when the host having the KLJN filter is receiving a key, by closing the first sub-filter to Johnson noise and opening the second sub-filter to Johnson noise.

19. The method according to claim 11 , wherein the wired network is an existing infrastructure network.

20. The method according to claim 11 , wherein the wired network is a smart power grid.