Technology
How does a fingerprint scanner work?
A fingerprint scanner works by capturing the unique pattern of ridges on your fingertip and comparing it to a stored version. It reads the tiny hills and valleys of your print, turns them into data, and checks for a match to unlock a device.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how a fingerprint scanner works.
Step by step
- 1It images the ridges and valleys of your fingertip.
- 2Capacitive scanners sense the pattern electrically; optical ones photograph it.
- 3Software extracts distinctive points and converts them to a template.
- 4Each scan is matched against the stored template, not a raw image.
- 5The template is encrypted and stored securely on the device.
Frequently asked questions
- How does a phone recognize your fingerprint?
- It maps the unique ridge pattern into a mathematical template and checks whether a new scan matches the one stored securely on the device.
- Is your actual fingerprint image stored?
- Usually not — devices store an encrypted mathematical template, not a picture, and keep it in a protected area of the chip.
- Can two people have the same fingerprint?
- Effectively no; fingerprint patterns are unique enough that a match is overwhelmingly likely to be the same person.