Are Iris Scanners More Secure Than Fingerprint Readers?

Samsung announced the Galaxy Note 7, set to release on August 19. One of the more interesting features is the iris scanner. However, is it more secure than the fingerprint reader found on many phones today?

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How Fingerprint Readers Work

Fingerprint readers are pretty affordable. Many phones and some laptops have this technology. If your computer does not have one built-in, you can buy an external reader that you plug into the USB port.

On each of your fingers is a series of tiny friction ridges on the surface. The dermal papillae – small extensions of the dermis into the epidermis – form these ridges. The fingerprint is the mark that these ridges leave behind. Your fingers leave prints behind due to sweat secretions from the eccrine glands inside the ridges.

The three most popular types of fingerprint scanners are optical, capacitive and ultrasonic. There are other’s  (RF, thermal and pressure sensors) but we will just cover the main three.

Optical Scanners

Optical scanning is the oldest method of capturing fingerprints. It uses an optical image of your finger. Algorithms detect the pattern of your ridges by analyzing the light and dark areas of the image. Similar to cameras, optical scanners have different resolutions.

optical scannerHigher resolution scanners work better. Since this technology relies on LED arrays to light up your finger, it is too bulky for a phone. This type of scanner is the least secure, and easy to fool.

Capacitive Scanners

Most phones have capacitive scanners. This technology works by using tiny capacitor circuits to collect data about your fingerprint. The circuits store an electric charge and connect to a conductive plate, forming the surface of the scanner.

capacitive scannerWhen you put your finger on the plate, the electric charge slightly changes when your friction ridges touch the surface. The gaps between the ridges will not change the electric charge. Another circuit tracks these electrical changes while an analog-to-digital converter records the data.

Ultrasonic Scanners

Ultrasonic sensors work by using an ultrasonic transmitter and receiver. The transmitter sends an ultrasonic pulse and bounces it off your finger. Your friction ridges bounce the pulse back to the receiver. The spaces in between the ridges absorb the pulse. The pulse travels beneath the skin, so this technology can tell the difference between a real and fake finger.

ultrasonic scannerThe sensor detects mechanical stress and calculates the intensity of the pulse that bounces back. Leaving your finger on the scanner results in a more detailed, 3D image of your print. Because of this, ultrasonic sensors are more secure than capacitive sensors.

How Iris Scanners Work

Anatomy of the Eye

First, let’s examine the human eye. Our eyes have different parts: eyelid, pupil, sclera, iris, limbus, retina, etc. Although there are many areas of the eye, we are covering the main ones.

  • Eyelid: The fold of skin that covers the eye and protects it from damage.
  • Pupil: The pupil is a hole in the center of the iris that lets light hit the retina.
  • Sclera: Also known as the white of the eye, the schlera is the outer layer of the eyeball.
  • Iris: The iris is what gives you your eye color. It is a circular structure responsible for controlling the size and diameter of the pupil.
  • Limbus: The corneal limbus is the border of the cornea and sclera.
  • Retina: The retina is the third, inner coating of the eye that provides light-sensitivity. It transforms light into visible information.
human eye anatomyIris Scanning

I know, this is a lot to remember. However, we only have to focus on the iris. If you look into the mirror, you can see the thin, wavy lines that make up your iris. These lines form a pattern, and like a fingerprint, this pattern is unique to every person. This pattern is what the iris scanner reads.

Unlike a fingerprint reader, though, an iris scanner does not just take a picture of your iris and then compare it to its records. It directs a beam of infrared light at your eye. Infrared exposes your iris pattern better and works in the dark. Glasses and contact lenses also don’t interfere with the light.

galaxy note 7 scannerAfter the scanner records the iris image, the software turns the pattern into a code and compares it against a record of your iris on file. The Galaxy Note 7 has a dedicated iris scanner on the front of the device. Traditional cameras cannot do the job because of the difference in build.

So Which Is More Secure?

The winner is Iris scanners. Fingerprint scanners are cheaper, and they are less secure. We leave fingerprints behind on every surface we touch. The sensor also won’t work on excessively dirty or wet fingers. In contrast, the patterns that make up our iris are much harder to copy. Blinking cleans and protects our eyes, so iris scanners have an easier job.

The iris scanner on the Galaxy Note 7 still has downsides though. First, it only works when your eye is within 10-14 inches away. The safety concerns are still unknown. Shining a beam of visible light into your eye can cause damage. Even though the beam is infrared and invisible, only time will tell if it has an impact. Samsung even warns users not to hold the phone too close when you’re scanning.