How the fingerprint scanner on phones and laptops work.

There are many ways we can protect our stuff, from locks to passwords. None of these methods are completely secure since people can guess our passwords/pins and pick locks. We no longer only have the option to use passcodes, now we have other options using biometrics, the use of fingerprint scanners, iris scanners, and even facial recognition tools, these kinds of tools help it become more difficult for others to get into our phones/computers. Here we will concentrate on the fingerprint scanner on our phones, tablets, and computers.

Fingerprints are unique, not a single pair of people have the exact same fingerprints, not even identical twins. Fingerprints usually remain the same for the rest of your life. This is why fingerprints are perfect to use as locks on our devices.

There are two main types of ways fingerprint scanners work. The first kind of scanner is the Optical fingerprint scanners. These kinds of scanners are known to be the oldest way to obtain and compare fingerprints. These kinds of scanners mainly work by projecting led light. It captures an image of your fingerprint, The darker areas of the image being the ridges of the finger and the lighter areas, the spaces between the ridges. It uses algorithms to point out specific unique patterns on the surface, like ridges or unique marks.

This is how it works, the in-screen scanner passes the LED light to the finger, like when you are making a photocopy on a printer. There is a camera underneath the screen which obtains the image and compares it to the one that is already stored and unlocks. This kind of scanner is mainly used on bigger bulkier phones, which is the reason it isn't being used as much, One of the first phones that used an optical fingerprint scanner was the Motorola Atrix, in 2011. This scanner captures 2D images, this means it is a little easier for a person to cheat the system, by using prosthetics and decent picture quality.

There is another kind of scanner known as the Capacitive scanner, this is the most common scanner being used for fingerprints. It is very similar to optical scanners. In which they both obtain an image of your finger, using the ridges and spaces between, know as the valleys. There is one main difference between the two which is that Capacitive scanners use electrical currents instead of using LED lights. These scanners use small capacitors, which are devices used to store an electric charge. They use an array of circuits, known as cells, these cells are smaller than the width of one ridge on a finger and are used to obtain data from a fingerprint. The scanner obtains the voltage output, processes it and determines whether it is characteristic of a ridge or a valley. By reading every cell in the sensor array, the processor can make up a picture of the fingerprint, just like an image captured by optical scanners. Capacitive scanners need to have a real fingerprint shape, unlike optical scanners who only require a decent picture or anything resembling a fingerprint. It is the most common scanner used in smartphones, and it the most secure.

When we are setting up our fingerprints to be used as codes to open up our devices, each print is analyzed for very specific details. When you place your finger on the reader, censors can draw out the ridges of your finger, When scanned it measures the distances and angles of our lines and then uses algorithms that take the details of your fingerprint and converts them into a digital template. This template represents your fingerprint, it’s like a drawing of it. They are converted by a one-way encryption algorithm. After the process, it is stored in a database, they do not store your whole figure print but only specific points/details, known as minutia points.

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