What is Touch ID? How does Touch ID work?

The first generation iPhone was born in 2007. Through decades of development with many versions introduced to users, iPhone has become stronger and smarter. One of the most effective features on the new generation iPhone model is Touch ID - fingerprint sensor. Not only does it help you lock / open the phone faster, Touch ID is also used in many security features and other utilities.

What is Touch ID?

For years, the iPhone only uses basic security with a 4-digit or 6-digit PIN and integrates a Find My iPhone service to find lost devices. In parallel with the advent of iOS 7 and iPhone 5s, Apple has upgraded iPhone security technology to a new level, which is Touch ID fingerprint sensor feature.

Touch ID, also known as fingerprint sensor , is equipped by Apple iPhone 5S and later generations. Touch ID is integrated directly into the physical Home button, allowing to open iDevice device easily by pressing the finger on the Home button. From iOS 10 platform or above, you can use Touch ID to quickly login Apple ID account in App Store or iTunes Store to install apps, buy music, movies . with 1 touch.

Touch ID.

How does Touch ID work?

Why can each Touch ID sensor work only with a single A7 chip? Through information from two patents filed by Apple in March this year, people have partly explained the above problems.

Why does a Touch ID sensor only "play" with a A7 chip of that machine?

Because inside each A7 chip is divided into at least two parts: "Secure Enclave Processor" (SEP) and "Application Processor " (AP). In particular, AP is the area used to handle common tasks of the machine, while SEP is a specialized area to store fingerprint maps that the iPhone can scan the owner. SEP is located inside the A7 chip, but it is not linked to any other components except the Touch ID sensor.

You can imagine that the A7 chip is a prison and SEP is like an extremely strict solitary room that can only be opened from a key, the information inside SEP will not be uploaded to the Apple server. upload to iCloud and share it to any developer. Touch ID is the key, the only way to connect to SEP to exchange and compare fingerprint data. While this cannot explain 100% of the above question, it also partly helps us know how it works.

Touch ID is the key, the only way to connect to SEP to exchange and compare fingerprint data.

Working structure of Touch ID

When first scanning fingerprint with Touch ID, this sensor will not store fingerprints in the form of images but in the form of charts (with pointed columns protruding like a heartbeat), and create an additional chart mini based on the main chart, has a lower resolution but contains important points and information unique to the big chart. The machine will then store the chart inside SEP, and encrypt it again. The reason why the device does not save the fingerprint chart into the AP is because the AP is not encrypted, the bad guys will be able to access this area, steal information from it to fake fingerprints. If saved in an isolated SEP zone, the chance of stealing information is almost zero.

Speaking of this mini-chart, although it has a lower resolution but contains the most important data of a fingerprint, it has enough data to remove incorrect fingerprints as well as authentically correct Hand of the owner of the machine.

Each fingerprint scan to unlock, Touch ID will redraw the chart of that finger.

Each fingerprint scan to unlock, Touch ID will redraw the chart of that finger, create a mini chart and use the power of the AP to compare the master chart saved in SEP. The reason why comparing mini charts and not big charts is because of two factors:

1. First : the mini chart still contains enough important information for authentication.
2. Second : mini charts have low resolution, thus saving chip processing time. That's why iPhone 5s can read fingerprints almost instantly. Imagine imagining bringing SoC chips today (with the power to handle 3D games dozens of frames per second), comparing two low resolution mini-graphs.

From iPhone 5s allows you to scan your finger in many different posture positions, if you only compare fingerprint images (but not compared to charts) then surely there will be many difficulties in comparing two images Different photos as well as spend a lot of time processing. In comparison with graphs, even though scanning fingerprint images are different, Touch ID can still create mini charts with the most common features of that fingerprint and easily compare with the chart saved in SEP. .

Wayne Westerman, Byron Han and Craig Marciniak are the authors of this patent, which is filed with the agency in March 2013. In it, Wayne was the main inventor, and he was also one of the inventors of multitouch technology in 1998, after which Apple acquired Wayne Technology and Fingerworks in 2005. and brought it to the first-generation iPhone in 2007. Opening the era of multitouch phones like today.