Biometric security systems that rely on fingerprint recognition have always had an easily exploited weakness in that they can be fooled by anything bearing a copy of the expected fingerprint. Now, a new development from Japan eliminates that flaw.

NTT's breakthrough allows fingerprint sensors to determine whether or not they are in contact with a real human finger by passing electricity across two electrodes [Subscription link].

Plastic fingers rejected

The conductivity of a flesh and blood digit is easily recognised and can be distinguished from a plastic copy that contains the same fingerprint pattern.

NTT plans to add the relatively simple technology to its sensors with a view to regaining some of the market share lost to finger- and palm-vein readers over the last couple of years.

In Japan, many bank ATMs use a biometric scanner to verify account holders' identity, which goes a long way to creating a market that will be worth around ¥40 billion (£200 million) there in 2010.