Fingerprint payment, based on fingerscanning, is the most common biometric payment method. Often, the system uses two-factor authentication, in which the finger scan takes the place of the card swipe and the user types in a PIN (personal ID number) as usual.
In the United States, biometric payment has gained popularity in grocery stores, gas stations, and convenience stores. In March 2006, "Pay By Touch", the leading biometric payment provider, reported that more than two million customers had enrolled in their biometric services and that "Pay By Touch" had authenticated approximately eight billion dollars in transactions.
The system of biometric payments is controversial. Traditionally, fingerprints have been associated with law enforcement. Critics of biometric payment fear that fingerprints could be made available to government agencies or law enforcement officials.
Biometric payment service providers are quick to point out that they don't keep the customer's actual fingerprint in their databases. They keep an encrypted number derived from the finger's point-to-point measurements. It is that number which is used to verify a customer's identity, not the actual fingerprint.
In the final analysis, a biometric payment system; like any system that accesses sensitive information, is only as secure as the associated databases and transactions.