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Touch ID on Apple iPhone – What is it? Security, Functioning and Setup Tips



Apple Touch ID Sensor

When Apple introduced the Apple iPhone 5s, there was a very new feature introduced, and this feature was not seen in any other smartphone because of the technology used in it – the Touch ID, i.e. the fingerprint recognition feature. What the Touch ID basically does, is reading your fingerprint and automatically unlocking your phone. The same Touch ID can be used to authorize the payments and purchases made from iTunes Store, App Store, iBooks Store.

Apple Touch ID Fingerprint

Touch ID feature was included first in the Apple iPhone 5s, and the technology was implemented after Apple acquired AuthenTec in 2012. AuthenTec is a company focused on the software for fingerprint reading and identification.

Understanding the Hardware of Touch ID

The Touch ID, i.e. the biometric fingerprint recognizer is located in the home button of the iPhone, and the Touch ID measures a thickness of just 170 microns. The sensor uses capacitive touch for detecting the user’s fingerprint, and the resolution of the sensor is 500 pixels per inch.

The home button is made of Sapphire crystals, and it protects the sensor, and acts as a lens to focus it on your finger. Around the button is a steel ring, which tells the Touch ID to start reading the fingerprint, whenever a finger touch is detected.

Functioning of the Touch ID

Apple says that the sensor uses the advanced capacitive touch technology to take high resolution images, capturing from small sections of the fingerprint, from the subepidermal layers of the skin. It then would analyze the information and categorize the fingerprint as one of the three types – arch, loop or whorl. Then the mapping of the individual details in the ridges is done, and the sensor would also check for the minor variations in the ridge direction caused by pores and edge structures.

Apple Touch ID Fingerprint Types

The detection can be done with the finger oriented in any direction, with the 360-degrees of orientation and recognition although the finger may be in any direction. The Touch ID sensor creates a mathematical representation of the fingerprint and matches it with the fingerprint data which is enrolled and saved, and once the match is found, the screen is unlocked.

If at all you place your finger in different positions, the new sections of your fingerprint to the enrolled fingerprint data in the iPhone, and this improves the matching accuracy over time.

How secure is Touch ID and the fingerprint data

Apple A7 ChipThe Apple’s Touch ID technology is quite secure, and one cannot easily bypass the lock screen or authorize transactions if you are not the owner of the iPhone and if the fingerprint is not registered in the device. There are no images of the fingerprint stored in the device. It just records and keeps the mathematical representation of the fingerprint, and there us a security architecture that Apple uses to store the fingerprint data.

This new security architecture is called Secure Enclave and that is embedded within the Apple’s A7 chip. The fingerprint data is encrypted and protected with a key available only to the Secure Enclave, and it is only the Secure Enclave which does the matching of the data. Being a part of the A7 chip, the data is never shared with any other app, and is not stored even in the iCloud or Apple servers.

In 2013, the German Chaos Computer Club said that it was able to bypass the Apple’s Touch ID security, and they criticized Apple and the misconceptions about the fingerprint biometrics, but it was later found out that the bypass wasn’t really easy, and someone should have a high resolution photocopy of the fingerprint, a few special chemicals, expensive equipment and thus, bypassing the lock screen is not that easy.

How to setup Touch ID

For you to enhance the security on your Apple iPhone, you need to activate the Touch ID. The initial iOS Setup Assistant would help you do that, or you can directly go to Settings > Touch ID & Passcode. To set it up, first a passcode has to be set, which would act as a secondary or backup security if at all the Touch ID doesn’t work or recognize at some point.

Follow the below steps to enroll the fingerprint and setup the Touch ID.

  • Make sure your finger and the home button are clean and dry.
  • Hold the iPhone in a position how you normally hold it while pressing the home button.
  • Touch your finger on the home screen and hold it at the same position until a quick vibration is felt and you are asked to lift the finger. There is no need to press the button, just a gentle touch is enough.
  • Continue lifting the finger and placing it back, making minor adjustments each time you do it.

Apple Touch ID Setup

Once the initial scanning of the finger is done, you would next be asked to adjust your grip to capture the edges of your fingerprint. This time, you are going to touch the adjacent outer areas of your fingerprint, instead of the center.

You can choose to use only the passcode if you didn’t want to use the Touch ID, especially when it is a phone which a few people wanted to use it. But as Apple suggests, you can register a total of five fingerprints in the iPhone.


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