Best answer: Like most Android phones you can buy today, the Galaxy S20 uses a software-based face unlock solution. It's secure, but not as secure as a biometric authentication system like the fingerprint reader.
- Turbocharged: Samsung Galaxy S20 ($1,000 at Samsung)
With face unlock on the Galaxy S20, you're trading security for convenience
The Galaxy S20 features a face unlock system that's identical on most Android phones. Facial recognition on the S20 relies on the front camera and software algorithms that match your facial features with a visual model that you create while setting up face unlock. The upside to this is that face unlock is nearly instantaneous: just hold up the S20 to your face, and your features are immediately authenticated.
It's definitely faster than the fingerprint reader. The Galaxy S20 comes with an ultrasonic under-screen reader that takes over half a second to authenticate, and next to that facial recognition feels incredibly fast. Unfortunately, there's a downside. Since face unlock is primarily software-driven, it is not as secure as biometric authentication.
There's no additional sensor providing depth data, and as such, it is possible for someone else to gain access to your phone with your facsimile. It's easy for facial recognition systems like the one on the S20 to be fooled by a photo, and if you're looking for a more secure authentication system, your best option is the fingerprint reader.
There are brands that offer secure face unlock, with Google making the switch with the Pixel 4 series. The Pixel 4 has two infrared cameras that take a detailed depth map of your facial features, and there's also a flood illuminator and dot projector that combine to create a 3D model of your face. Think of it this way: with a software-based model like the one on the Galaxy S20, you get a 2D model of your face that can be fooled by a photo. The Pixel 4 and the latest iPhones use custom hardware to create a 3D model, making their face unlock solutions just as secure as the fingerprint sensor.
So if you're using face unlock on the Galaxy S20, know that it isn't as secure as a PIN or the fingerprint reader.
The most feature-packed phone in 2020
With a sublime 120Hz AMOLED panel, the latest internal hardware with 5G connectivity, and upgraded cameras, the Galaxy S20 ticks all the right boxes. You're paying a lot of money for this phone, and you're also getting a boatload of features in return.
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Harish Jonnalagadda is a Senior Editor overseeing Asia at Android Central. He leads the site's coverage of Chinese phone brands, contributing to reviews, features, and buying guides. He also writes about storage servers, audio products, and the semiconductor industry. Contact him on Twitter at @chunkynerd.