The invention relates to methods and apparatus for Quantum key distribution. Such methods including authenticating a first node in a communications network with a remote node in the communications network. The authentication may include connecting an authentication device to the first node, agreeing a quantum key between the first node and the remote node based on a quantum signal transmitted or received by the first node and performing an authentication step between the authentication device and the remote node on an encrypted channel. Authentication between the authentication device and remote node may be taken as authentication of the first node.