Taking charge of biometric power consumption

August 18, 2020

Fredrik Ramberg, SVP of R&D at Fingerprints

Biometrics has come a long way since it was first used in an Argentinean court case in the late 1800s. No longer just a tool to solve murder mysteries, consumers have embraced biometric technology in their daily lives, with 82% of consumers that have access to some form of biometrics on their mobile phone actively using the technology.

Use cases beyond mobile are also on the rise, with several rollouts of biometric payment cards scheduled for later this year and access sensors being integrated in a range of consumer devices, including smart suitcases. Yet some consumers remain skeptical about the convenience of biometrics. After all, the benefits of biometrics in mobile are easy to see – they offer consumers a more convenient and secure way to unlock phones and applications – but what about other use cases? Wouldn’t it be a hassle to charge your debit card every other day just to be able to pay for your groceries?

The concern makes sense. Smartphones have big batteries able to power biometric sensors alongside all their other applications, so it’d sound plausible that new form factors, such as biometric payment cards, would need large batteries. In turn, creating a considerably impaired UX for use cases that traditionally don’t need charging.

Luckily, however, this concern is unwarranted. Modern, ultra-low-power biometric technology makes it possible to power sensors from a reader or point of sale (POS) terminal at a tap, allowing biometric solutions to deliver greater security to consumers in a wide variety of use cases without infringing on the UX.

Let’s unpack, then, how biometric technology is taking charge of its power consumption.

What’s in a name?

Once biometrics entered the mobile industry, our R&D team began optimizing the power of sensors so they would not compete with power-hungry processors and did not use any power when inactive.

While the mobile sensor market boomed, it was clear biometrics had potential to enhance so many other aspects of daily life. It was important to look beyond mobile – to embedded applications where a large back-up power source, such as the battery in a smartphone, is not always available. Developing even lower-power sensors was a key priority for our company.

After all, the company isn’t called Fingerprint Cards for nothing.

By championing a design strategy for low-power biometric sensors right from the start, over time we have been able to optimize and finetune our sensor designs for low-power embedded applications.

Now, as biometrics gathers momentum in new industries, such as payments and access control, Fingerprints’ technological edge in low-power sensors is starting to pay off.

Low power, high security

Just as in mobile sensors, biometric sensors in cards use no power when inactive, but crucially, they only use a minimal amount of power when in use.

By deploying such low-power biometric sensors in payment cards, the sensors can harvest energy collected from readers and the NFC fields in the same way that, for example, contactless cards are powered by POS terminals. In the payment card example, the entire fingerprint authentication process, consisting of an image capture and matching, consumes so little power that it can harvest the energy it needs from the terminal, without impacting the operation of the secure element (SE). From a privacy and security perspective, this means that the entire operation is performed on the card without any information being transferred to the terminal, meaning consumers and banks alike can rest assured that no sensitive biometric data ever leaves the hands of consumers.

As a result, biometric payment cards forgo the need for a battery and can deliver the same UX of contactless, just with greater security. But of course, the possibilities don’t end with payments. The same ultra-low-power technology is also being used for other ultra-low-power applications, such as access control cards, small fobs and rings.

The power is in the detail

To achieve this level of power-efficiency without compromising UX, it’s important to get a few details right.

Firstly, you need to optimize every part of the system from start-up to image capture and read-out, to ensure that you can operate fast without generating any current peaks. Superb system performance is also key to reducing the complexity of image processing or the need to take several images. Achieving this is no mean feat and delivering the highest quality sensors is an ongoing effort – our R&D team has spent the last 20 years optimizing and fine-tuning sensing pixels and system architecture to ensure superb system performance while maintaining ultra-low-power consumption.

You also need to meet the power requirements of the existing infrastructure – in the case of payment cards, the existing POS terminals – to be able to introduce biometrics without disrupting legacy systems. The key here is to optimize for the lowest power consumption terminal to ensure biometrics works across them all.

Lastly, it is important to keep power consumption relatively consistent and below a certain peak to avoid faults in the communication with the terminal.

Depending on the implementation, features and functionality can be tuned up or down to meet the requirements of specific use cases or existing infrastructure ecosystems. Reading an image over a longer period of time, for example, consumes less power. But when you increase the image reading time, you require the finger to stay on the sensor for longer, which increases the likelihood of a moving finger and therefore creating a blurry image and rejection.

Because our sensors have a low enough power consumption and a fast-enough read-out time to be compliant with 100% of current payment terminals, we have been able to optimize all the trade-offs that traditionally hinder low-power sensors. Getting these details right has allowed our sensors to meet the stringent set of requirements of the payments industry, leading to the first commercial certification by a global payment network.

Done once, done right

Using the latest ultra-low-power sensors, it is possible to have a completely contactless, battery-free biometric card that works in the same way as today’s payment cards. This has changed the game for payments, creating both a more secure and more convenient authentication process.

But most industries don’t have such a stringent set of requirements and complex existing infrastructure as the payments industry.

Getting biometrics in payments right means that rolling out biometrics in other use cases – such as access control cards and fobs – will be less complicated from a power perspective.

The ability of low-power sensors to integrate biometrics into a wide variety of form factors will bring many benefits to consumers. After all, its endless possibilities to make consumers’ daily lives more convenient and secure is surely biometrics’ greatest power.

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