Some smart cards include a digital template of the owner's fingerprint so users won't have to remember PINs or passwords when, for instance, making purchases over the Web. But the idea of fingerprinting bothers many people. Swindon, England-based Domain Dynamics is putting voice templates on smart cards, so users can authenticate transactions using their voices. Standard voiceprints require the storage of more data than can fit on the chip embedded in a smart card; but Domain Dynamics' voiceprints are one-tenth that size. Conventional methods describe voice based on the amplitude of sound waves at millisecond intervals, but Domain Dynamics uses a simpler method that describes each wave's overall shape. When a user speaks, the card's tiny processor matches the voice with the stored template. Domain Dynamics is working with several companies to make the technology available for banks as well as for cell phones and personal digital assistants; the goal is a product within the next two to three years.