How your fingerprint became the key to your computer
You store your entire digital life in your laptop, so it makes sense to lock it down and keep it safe. And as far as keys go, the finger is mightier than the password. Some modern laptops, such as the ASUS ZenBook 3, have fingerprint authentication to make sure you, and only you, can access the important stuff on your computer.
The fingerprint scanner, along with Windows Hello, gives your laptop the high-grade security you enjoy on your smartphone. Windows Hello even identifies the fingerprints of several different users if it’s a shared computer,
But maybe you’re wondering, how did scientists determine that fingerprints should be the key to our digital homes?
Some historians trace the history of fingerprint identification back thousands of years, to cave paintings where artists would identify themselves using prints of their hands; others trace it to pioneering police detectives who started cataloguing fingerprints in the 19th century.
The most influential of these pioneers is a French anthropologist and police officer, Alphonse Bertillon, who proposed several scientific methods for identifying criminals. Bertillon’s work led later scientists to propose a 16-point system of the fingerprint, which is the basis for modern fingerprint identification.
The actual technology that lets your fingerprint unlock your laptop really gets cooking in the 1960s. By this point, scientists had figured out that a fingerprint was basically a series of ridges and valleys, where the ridges pop out slightly from the skin and the valleys are closer to the finger.
Measuring the placement of these ridges and valleys revealed that no two fingers formed identical prints. Fingerprints can contain dots, which are tiny ridges, and islands, which is a ridge that is not connected to another ridge, and ponds, which is a totally empty space between two ridges. With all of these features, your fingertips contains a unique identifier for you and only for you.
So, in the 1960s, university researchers and U.S. law enforcement searched for a way to automate the process of both intaking and storing fingerprints. As computers became more powerful, scientists figured out a way to both scan in fingerprints and automatically read them for identification purposes.
Eventually, two types of computerized fingerprint readers were developed. The first, the optical scanner, takes a picture of your fingerprint and compares it to a photo it keeps on file. This is the kind you might recognize from old spy movies, where a green laser bar scans a handprint like a grocery store cashier.
Your ZenBook 3, and most smartphones, use the capacitive method. This method uses capacitors, or small electric cells, to measure those valleys and ridges on your finger. So if a capacitor is under a ridge, the capacitor sends one kind of signal; if a capacitor is under a valley, it sends another kind of signal.
These signals are all taken together and then compared to the encrypted information about a fingerprint that the computer has on file. This all sounds more complicated than it is in real life—with Windows 10 notebooks equipped with a fingerprint sensor, like the ZenBook 3, Windows Hello takes care of all of this. If your fingerprint matches the master print on your ZenBook 3, your computer is unlocked and Windows Hello logs you straight into your account in a split second.