Realizing long-term quantum cryptography

We present a set of long-term quantum key distribution (QKD) results from the QuantumCity initiative in Durban, South Africa. Many QKD experimental setups have failed to provide a long-term analysis of QKD systems in commercial environments. Long-term analysis of the stability and performance of these systems is an imperative step towards the market acceptance of QKD technology. The Durban-QuantumCity project intends to develop a multi-user quantum communication network that is currently overlaid on the fiber infrastructure of the eThekwini Municipality. The first phase of this project includes the deployment of a four-node star network. To date, two links have been deployed and one link has run continuously for a number of months. We provide a brief overview of practical implementations of quantum networks and the first set of results from the live data encryption of the QuantumCity project. © 2010 Optical Society of America.