Hi, is it really you? 喂，真的是你嗎？

Vocabulary: travel fraud 詞匯: 詐騙

People who want you to part with your cash and property can steal your passwords and personal details, but what about your voice?

That's what some big companies asked themselves before turning their attention to voice biometrics in their war against fraudsters.

Emmanuelle Filsjean, head of marketing for a company which advises retail banks on security, says: "Voice is a dynamic form of biometrics, rather than static like a fingerprint. It's harder to replicate and copy digitally."

Digital voiceprints contain over 100 identifiable elements. And, by using complex mathematical algorithms and the latest high-definition audio equipment, experts believe they can now identify people accurately more than 97% of the time.

Even identical twins can be told apart from their voiceprints, making the technology reliable enough to be used as evidence in courts of law.

Voice is crucial because call centres are still the main way we interact with companies, despite the rise of online banking and shopping.

Traditional authentication measures, involving personal identification numbers (PINs), passwords, and 'memorable' answers to agreed questions, have proved fallible because we keep forgetting them. But voice is the most natural way of interaction.

While no biometrics security system is totally foolproof, fraudsters using high definition recordings of someone's telephone pass phrase should still be caught out, according to voice biometrics companies. They say even the highest-quality recordings use some form of compression that changes the highest and lowest frequencies.

Even a slight mismatch with the customer's voiceprint will trigger a 'live test' conversation that is almost impossible for fraudsters to spoof, particularly if they've only got a recording to use.

It's no surprise so many companies are keen to hear the latest word in security systems. Fraudsters are stealing at least ￡52bn from the UK economy each year, according to the National Fraud Authority (NFA).