77 day field trial of high speed quantum key distribution with implementation security

Quantum key distribution’s central and unique claim is information theoretic security. However there is an increasing awareness that the security of real QKD systems relies not only on theoretical security proofs, but also on how closely the system matches the theoretical models and resists known attacks. These hacking or side channel attacks exploit physical devices which do not necessarily behave precisely as the theory expects. As a result there is a need to demonstrate QKD systems providing both theoretical and implementation based security. We report here a QKD system which has been designed to provide these features of resistance to real security issues, component monitoring and failure detection – important not only from a security point of view but also for reliable and robust operation. Alongside the increased security confidence level the system operates with a high and stable secure key rate due to newly developed active stabilisation, averaging 210kbps and producing 1.33Tbits of secure key data over 77 days in a telecom network.