Abstract: A system and method are provided for mitigating key-exhaustion attacks in a key exchange protocol. The method includes computationally confirming an exchange of key bits has provided fresh shared key material before information theoretically confirming the exchange of key bits has provided fresh shared key material, while maintaining synchronization between messaging parties. In one implementation, maintaining synchronization includes updating keys in between each post-processing message session and managing a local state of each messaging party in the key exchange protocol prior to sending a next post-processing message. In another implementation, maintaining synchronization includes hiding a message containing the information theoretic authenticator by executing a decoy authentication process, prior to using an information theoretical key.

Abstract: A system and method are provided for proactively buffering quantum key distribution (QKD) key material. The method includes monitoring key generation rates and surpluses at QKD devices at each node of a QKD link in a QKD network, retrieving surplus key material from the QKD devices at one or both nodes of the QKD link, and buffering the surplus key material in a local storage at one or both nodes in the QKD link. The surplus key material can be used to offset overhead introduced in securely relaying keys between non-adjacent demand pairs in the QKD network. The surplus key material can also be used to offset future transient decreases in key generation rates.

Abstract: A system and method are described for proactively performing key swaps among nodes in a quantum key distribution (QKD) network. The method includes determining a routing solution for nodes in the QKD network; making the routing solution available to the nodes in the QKD network; and initiating key swaps among the nodes in the QKD network according to the routing solution, prior to key requests being made within the QKD network. The method can also include continuously performing key swaps among the nodes in the QKD network according to the routing solution; detecting a change in capacity and/or a change in demand on one or more links within the QKD network; determining a new routing solution based on the detected change; and continuously preforming subsequent key swaps according to the new routing solution.