Quantum Information Group, Toshiba Quantum Key Distribution System
Toshiba's Quantum Key Distribution System delivers digital keys for cryptographic
applications on fibre optic based computer networks. Based on quantum cryptography
it provides a failsafe method of distributing verifiably secret digital keys, with
significant cost and key management advantages.
The system provides world-leading performance. In particular, it allows key distribution
over standard telecom fibre links exceeding 100 km in length and bit rates
sufficient to generate 1 Megabit per second of key material over a distance
of 50 km — sufficiently long for metropolitan coverage.
Toshiba's system uses a simple ‘one-way’ architecture, in which the
photons travel from sender to receiver. This design has been rigorously proven as
secure from all types of eavesdropping attack. This ensures that the Toshiba design
will be secure not only today, but also in the future.
Toshiba has pioneered active stabilisation technology that allows the system to
distribute key material continuously, in even the most challenging operating conditions,
without any user intervention. This avoids the need for recalibration of the system
due to temperature-induced changes in the fibre lengths. Initiation of the system
is also managed automatically, allowing simple turn-key operation. It has been shown
to work successfully in several network field trials. The system can be used for
a wide range of cryptographic applications, e.g., encryption or authentication of
sensitive documents, messages or transactions. A programming interface gives the
user access to the key material.