BiometricsBank customers can designate one finger as "panic finger"

Villains, beware. The fight against online fraud has a new weapon — the panic finger. Banks in Europe and South Africa are testing a device which authenticates online transactions by asking customers to run their fingerprint over a reader. If the print matches a stored copy, the device, which is made by Siemens, a German firm, and AXSionics, a Swiss firm, shows a PIN code that can then confirm the transaction. Consumers can enrol more than one finger when they start using the scanner. That adds yet another layer of security: worrywarts can set the device to require a concerto’s worth of fingerprints before it gives out the PIN code. It also allows people to designate a panic finger, for use if fraudsters are forcing customers to use the device. Swipe the said digit across the scanner and the transaction will appear to go through as normal even as the bank is alerted that something fishy is going on. For the truly neurotic, there is yet more reassurance. Criminals who are tempted to hack off customers’ fingers will be disappointed: the scanner has to detect circulating blood to work.

All very ingenious — but, asks the Economist, will it take off? The technology is fast improving and the algorithms used to read fingerprints are more reliable than ever. Consumers value security. According to a survey of American bank customers in 2007 by Gartner, a research firm, more than half rate security features as extremely important when deciding whether to go online. Banks gain too. It is harder for customers to repudiate transactions when their fingerprints are all over them. Two big hurdles remain, however — convenience and cost. Training customers to use something new is never easy. Scanning fingerprints adds time as well as security. Also, the device is another thing to lose or break. Systems based on voice biometrics look more user-friendly: people already use telephones, and can do so on the move. Voice signatures can also make transactions swifter, by cutting out the need to enter account details.

The Economist says that the economics are an even bigger barrier. The costs of the technology are coming down, but the device is still more expensive than other systems. Creating passwords costs virtually nothing and smart-card readers for use at home are much cheaper too. Fingerprint scanners are not for the mass market, says Avivah Litan, an analyst at Gartner, who does think that voice biometrics will be in widespread use in America within three years. Siemens says that banks serving affluent customers are most likely to use its technology-fingers firmly crossed, that is.