Patent ID: 8681982
Filing Date: 2014-03-25
Classification: H04L

Abstract:
1. A method of establishing a quantum key for use by first and second network nodes, the method comprising a key agreement step and an authentication step, and wherein the key agreement step is performed by the second network node and a third network node, and the authentication step is subsequently performed by the first and second network nodes, wherein in the key agreement step the second and third network nodes exchange messages over a classical channel, and in the authentication step: [i] said messages are passed from the third network node to the first network node; [ii] the first and second network nodes each locally generate a cryptographic hash of said messages using an authentication key shared by the first and second network nodes; [iii] the first and second network nodes exchange the cryptographic hashes generated in [ii] so that each receives a cryptographic hash from the other; [iv] received and locally-generated cryptographic hashes are compared at each of the first and second network nodes.