Design and construction of a high speed quantum key distribution device
Stuart Holt · The University of Queensland · 2001
Quantum cryptography has been proven to be the only practical method for fast distribution of secret keys needed for encryption. It enables absolutely secure information transfer from one party to another and allows for the detection of an eavesdropper without sacrificing security. This project involved designing and building a quantum cryptography device. This device has applications in many fields, including internet security as well as military communications. The data are encoded on single photons, which are sent through free space over a distance of about 30 cm. The electronics, which control the device however, are equally suitable for operation with fibre optic cables. The device was designed to operate in dark conditions within a laboratory. Currently, no research group has demonstrated transmission speeds faster than 8 kb/s. The aim of this project was to achieve bit rates faster than 10 kb/s, while operating under strict economic constraints. Although quantum cryptography was not demonstrated in the laboratory due to problems with the detector, the emission end, which generates single photons of light with one of two different polarisations, was shown to work as it was designed. The current design has limited commercial future due to the dark conditions under which the communication must take place. The project however has demonstrated that quantum cryptography is getting closer to becoming a reality.