Amazon installed hand scanners in Whole Foods stores that lets shoppers pay with a palm print. Here's how they work.

• Amazon installed hand scanners at Whole Foods that allow people to pay with their palm print.
• The Amazon One system is being unrolled at seven Seattle Whole Foods stores.
• The company first released the new payment system last fall.

Amazon is installing a system that allows customers to pay for goods using the palm of their hand at Whole Foods stores in the Seattle area.

The company announced the payment system, called Amazon One, would be available at its Whole Foods store on Madison Broadway on Wednesday. The new system will be available across seven Seattle stores in the coming months.

The payment system works by scanning people's palms to identify distinguishing characteristics like wrinkles, veins, and bones. An individual's palm acts as a unique signature that is tied to their credit or debit card at the participating stores.

Shoppers can enroll in the new payment system at an Amazon One kiosk, or using one of the devices at the Seattle Amazon stores.

The sign-up process takes about one minute, according to the company. It requires shoppers to insert their credit or debit card and hover their hand face-down over the palm reader.

The kiosk then goes through a series of prompts that ties the card to the individual's distinct handprint. Customers can use both palms or even tie their Amazon Prime account to their palm print, in order to get special Prime services at Whole Foods.

The company patented its Amazon One software in 2019. The new payment system was first introduced at the company's Amazon Go stores in Seattle last fall. Since then, the Amazon One service has been added to several of its other stores, including, Amazon Books, Amazon 4-Star, and Amazon Pop-up.

Amazon said the palm scanner has multiple security measures for protecting shoppers' identity and the information is stored separately from customers' other data.

"The Amazon One device is protected by multiple security controls, and palm images are never stored on the Amazon One device," it said on Amazon's website. "The images are encrypted and sent to a highly secure area we custom-built for Amazon One in the cloud where we create your palm signature."

The palm print can also be deleted if a customer chooses to deactivate their Amazon One ID or does not use the service for over two years.