Fibre optic networks can be eavesdropped upon using equipment costing as little as $1,000, Swiss encryption specialist InfoGuard warned at this week's Infosecurity Europe Show.

During a demonstration session, the company showed how it was possible to tap into fibre links by opening up optical interconnect boxes of the sort buried in ground ducts, feeding spare data-carrying fibres through devices in such a way that small amounts of light 'escaped' the fibre by gently bending it. This signal was then amplified to reconstruct the information stream.

The same hack would work even for wave division multiplexing (WDM) by using a $10,000-worth (£5,000) of equipment capable of separating the different frequencies.

The company's solution to the issue is the InfoGuard Multilink Encryption, a heavyweight encryption appliance capable of handling many different types of data traffic between remote SAN datacentres, including Gigabit Ethernet, Fibre Channel, and SONET/SDH.

The product could, InfoGuard said, combine data streams from the different protocols, sending them in 256-bit AES encrypted and therefore secure form at throughputs up to 10Gbit/s. Despite the need to encrypt and decrypt all data moving on to and off the links, the company maintained that the Multilink introduced no latency.

"The idea of the appliance is to have a device that will provide encryption without any performance degradation. Our boxes have a throughput latency of between one and five microseconds, it's almost negligible," said InfoGuard's Bernard Everett.

The cost of a box depends on the throughput needed, with 1GBit/s starting at 26,000 euros (£20,700), and a 10GBit/s version costing 50,000 euros (£40,000). Businesses would need one box at either end of a link, doubling this cost.

The company demonstrated the same at last year's Infosecurity Europe Show to promote its encryption boxes, but the new Multilink hardware ups the flexibility and power of the technology, handling up to ten ports at once.

It also potentially ups the price for UK and US users - the euro has appreciated considerably against those currencies since last year's show, and the company's equipment is priced in euros.