MONEY has been transferred between banks using quantum cryptography for the first time. This novel technology promises to make exchanging information 100 per cent secure, and the latest feat brings it nearer to commercialisation.
The experiment was carried out last Wednesday by a team headed by Anton Zeilinger of the University of Vienna. The city鈥檚 mayor sent a donation of 鈧�3000 to the team, using data sent along an optical fibre threaded through sewers between Vienna City Hall and the Schottengasse branch of Bank Austria-Creditanstalt.
Encrypting and decrypting the message required a key, sent secretly from the transmitter to the receiver using pairs of entangled photons. Any eavesdropper would have disturbed the quantum entanglement and signalled their presence, as well as making it impossible to extract any information from the message.
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The commercial quantum cryptographic devices that already exist use a different system, employing weak pulses of light to create a secure key. Using pairs of entangled photons makes it easier to guarantee absolute secrecy.
Although the two buildings in the Vienna transfer were only 500 metres apart, Zeilinger says that it should be possible to extend such links to 20 kilometres. 鈥淚n three years, we鈥檒l have a marketable system,鈥� says team member Andrea Aglibut.