Patent ID: 9692595
Date: 2017-06-27
CPC Classifications: H04L

Claim:
1. A method of quantum key distribution comprising a quantum exchange step and a subsequent key agreement step, wherein, in the quantum exchange step, a first quantum node and a second quantum node exchange a quantum signal over a first quantum link and wherein the first quantum node communicates with a control node such that the control node has information regarding the quantum signal exchanged in the quantum exchange step, and the control node takes the place of the first quantum node in the key agreement step, the method further comprising determining a bit loss factor corresponding to the ratio between bits exchanged in the quantum signal and the number of bits used, or to be used, in the key agreement step, maintaining a certain level of loss in communications involving any of the first quantum node, the second quantum node and the control node, determining if the bit loss factor meets predetermined security requirements and, if the predetermined security requirements are not met, enhancing the security of the network by at least one of the following: increasing the bit loss factor, hashing the bits used in establishing a key, using an alternative or additional hashing function to increase the bit reduction in hashing, increasing the rate at which keys are replaced, sending portions of random strings for determining keys along different paths, in which the bit loss factor meets predetermined security requirements if the number of possible bit combinations used in key generation exceeds the number of possible keys which may be established in use of the network.