Towards practical quantum key distribution: the Eqcspot system

Quantum key distribution (QKD) is a new and promising approach for secure k ey distribution based on the physical laws of quantum mechanics. This paper describes the software architecture and the algorithms used in the protoco l of a QKD system, called Eqcspot, developed as an industrial application. The software system for the transparent key exchange consists of two applic ations running on two PCs that communicate through a message and queuing pr oduct, MessageWare Plus, on a LAN. The system interacts with the quantum ch annel through a software library and exchanges data on the net. The final u ser can interact with the system very easily thanks to a simple GUI client component. The key distillation algorithm used in the system is briefly des cribed in the paper. The quantum channel (QC) software library is a highly generalized module for different schemes of QC driver implementations. Fina lly the paper describes some initial results and future expansions of the s ystem.