<http://news.ft.com/cms/s/a0dcf3f0-5874-11d9-9940-00000e2511c8.html> The Financial Times Scientists close to network that defies hackers By Clive Cookson, Science Editor Published: December 28 2004 02:00 | Last updated: December 28 2004 02:00 Scientists have taken what they say is a big step towards an intrinsically secure computer network which banks and other institutions could use to transmit data without risk of hacking. Toshiba Research Europe is one of several laboratories around the world racing to commercialise quantum cryptography, a technology that uses quantum mechanics to generate unbreakable codes. The Cambridge-based company says it has produced the first system robust enough to run uninterruptedly for long periods without human intervention. The Toshiba researchers have tested the system with MCI, the international telecommunications company, and plan next year to carry out trials with financial institutions in London. Secure digital communication uses long prime numbers as keys to encode data at one end and decode at the other. Inquantum cryptography, individual photons - light particles - transmit the secret keys down optical fibres. Each photon carries a digital bit of information, depending on its polarisation. To outwit hackers, the keys are changed many times a second. The extreme delicacy of these quantum bits is both the strength and weakness of quantum cryptography. On the positive side, a hacker cannot eavesdrop on the data transmission without changing it and alerting sender and receiver to the breach of security. But the system is easily disturbed by tiny fluctuations such as temperature changes in the transmission apparatus or movements in the optical fibres. Previous quantum cryptography transmissions have lasted only for minutes and required continual adjustment by experts, says Andrew Shields, head of Toshiba's quantum information group. His laboratory managed to extend the running time to a week's "entirely automated and uninterrupted session". The Cambridge researchers stabilised the system and reduced the error rate by sending a bright "guardian pulse" of light down the fibres immediately after each information-carrying photon. Mr Shields said: "The technology is now sufficiently mature to be used in real-world situations and we are currently discussing applications with interested parties. In the first instance we expect quantum cryptography to be used in companies' private networks - for example, to provide secure traffic in a link between two sites within a metropolitan area." Besides Japanese-owned Toshiba, large electronics companies competing to commercialise quantum cryptography include NEC of Japan and Hewlett-Packard of the US. There are also two start-ups, Magiq Technologies of the US and ID Quantique of Switzerland, with first generation quantum cryptography products on the market, although sales have not been large. -- ----------------- R. A. Hettinga <mailto: rah@ibuc.com> The Internet Bearer Underwriting Corporation <http://www.ibuc.com/> 44 Farquhar Street, Boston, MA 02131 USA "... however it may deserve respect for its usefulness and antiquity, [predicting the end of the world] has not been found agreeable to experience." -- Edward Gibbon, 'Decline and Fall of the Roman Empire'