The chief executive and founder of Quintessence Labs was also a member of the Australian National University's Quantum Optics Group.

The unbreakable encryption system the love-child of the ANU physics department and the newly created Quintessence Labs was on show yesterday at National E-Security Week, which aims to promote secure communications.

Cryptography is the art and science of securing communications and is now said to be fool-proof.

Dr Sharma said it was a sign of technological maturity that many people didn't even know digital cryptography was employed, such as with secure, online banking. He said quantum cryptography would herald the end of digital encryption.

''For routine everyday information exchanges, if you make prudent use of classical encryption techniques, the technology is safe,'' Dr Sharma said.

''It's based on formulas that would take a current supercomputer 1000 years to break.

''But advances in computer power could render it obsolete in years. Or a mathematician could devise a new formula, or a new algorithm tomorrow. And with quantum computers, what would take a supercomputer 1000 years to break would only be a matter of hours.

''Quantum cryptography offers the only provably unbreakable cryptology system today.''

The ANU's Quantum Optics Group, of which Dr Sharma was part, won the 2006 Eureka prize for being one of the first in the world to provide an end-to-end cryptography system using a laser, rather than photons. With lasers, the signal receiver can see whether the ''key'' to decode the message has been tampered with.

''The messenger can't be compromised. With quantum cryptography, the lasers are so finely tuned that you would know as soon as somebody has tried to eavesdrop,'' Dr Sharma said.

''It's also a lot quicker to generate a key. And we're able to incorporate a lot of common equipment used by telecoms.

''It's more robust, more reliable and more readily available.''

Quantum cryptography needs fibre-optic infrastructure, such as that proposed in Labour's new fibre-to-the-node network. Any area where secure transactions are needed, there's a market for the technology.

A commercial prototype is expected to be field-tested by the middle of next year.

National E-Security Week, which ends on Friday, combines commercial entities such as ebay, Telstra and Microsoft with the Department of Broadband, Communications and Digital Economy, all of which have a stake in raising security awareness.