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[Other] [How it Works #2] Know More About Fingerprint Sensor!

2019-04-18 01:14:11
1753 85

Dear Mi Fans!

This is a new series about all parts your smartphones and how it works on device!
Almost all modern smartphones are equipped  - the Fingerprint sensor. But not all know how it work's! Today you know it and more about this smartphone detail.

We live in an era of total penetration of digital technologies in all spheres of life - we shop on the Internet, store money on cards, virtual accounts, and personal photos - in network storages. In this case, the protection of personal data becomes more relevant than ever. After all, the access of intruders to personal information can threaten us with big problems.

Especially vulnerable in this regard are smartphones, through which authorization occurs in many online services. And for these purposes, many manufacturers use fingerprint scanners to protect the user's personal data. The smartphone is easy to lose, and if lost, intruders can gain temporary access to it. In most cases, passwords or graphic keys are used to protect data in smartphones. But it is not always safe and convenient. A new stage in the safety of modern gadgets is biometric protection, based on the uniqueness of some parts of our body. For example, iris and retina, facial geometry, voice, fingerprints. Using the process of biometric authentication is reliable and convenient protection - but this is not always the case and is not secure (let's talk a bit later). Just such a "password" can not be forgotten, pry, extremely difficult to fake and it is always "at hand." We will understand the work and capabilities of fingerprint scanners. This method of identification is based on the unique pattern of papillary patterns of human fingers.

It is characterized by ease of use, reliability and versatility, but it is also easy to fake (an impression or a photograph, option 2 is more complex). Fingerprint recognition is performed using a special scanner, which reads the papillary pattern, transforms it and compares it with a standard. There are three basic scanning methods:

1. Optical

Such a scanner is actually a small digital camera. The light emitted by the LEDs is reflected from our finger and hits the photosensitive matrix, which converts the optical signal into digital. It is not the image of the print itself that is read, analyzed and compared, but its geometry — the distance between the lines, the shape, the curvature. There are two main types of optical scanner. The first is when you take a snapshot of the desired area of ​​the finger when you touch the scanner.

In the second type of optical scanner, we have to drag your finger across the scanner. The scanner takes a series of images and combines them programmatically into one. This method is called ling (swipe). It was implemented by Samsung in the Galaxy S5. But in subsequent models, she abandoned this method. Because of the need to use a larger matrix for a full fingerprint image, the first type of optical scanner is more expensive than a lingering, but at the same time more convenient for the end user. A common drawback of optical scanners is susceptibility to dirt, scratches, and the influence of the physical state of a finger (moisture, for example). In addition, such a scanner can be fooled using a fingerprint snapshot, which was successfully demonstrated by a group of hackers Chaos Computer Club. They photographed in high resolution a fingerprint on the glass, printed it on a laser printer, filled it with liquid latex, and after drying such an impression was recognized by the scanner system as a native one. Thus, it was possible to circumvent the protection of the offspring of both Samsung and Apple.

2. Semiconductor

Based on the properties of semiconductors to change their properties at the points of contact. Such scanners are capacitive, radio frequency, thermal. In modern smartphones, semiconductor scanners have not found a place. Probably due to the complexity of implementation given the small size of mobile gadgets, as well as the high cost. A big plus of this technology is that you cannot fool it with the help of an impression.

3. Ultrasound

In my opinion, the most promising method of the fingerprint scanner. Ultrasound scanners use the principle of medical ultrasound to create a visual image of a fingerprint. Sound waves are generated using piezoelectric transducers. Then they fall on the finger and the echo reflected from it is fixed by special sensors. Unlike optical images, these scanners use very high frequencies of sound waves that are able to penetrate the epidermal layer of the skin. And it has a unique structure.

This eliminates the need for a clean, dry, intact finger. An ultrasound scanner cannot be deceived with a fingerprint image, since it forms a 3D picture of the structure of the skin, and also knows how to capture the pulse. In March of this year, Qualcomm introduced its development based on this technology and it is rumored that for the first time we will see its implementation in the Xiaomi Mi5 smartphone CMOS matrix

The coprocessor is responsible for processing the scanned fingerprint, and the already converted digital code is stored only in a special isolated storage. With the help of a fingerprint scanner, you can unlock a smartphone and log in to various payment systems, take a photo and much more. It is also supported by many third-party applications. Already implemented payment using Fingerprint with G Pay, and the ability to use a scanner to protect data from third-party programs.

In smartphones on the Android operating system, the fingerprint scanner first appeared in the Motorola Atrix 4G, but due to the inconvenience of the implementation was used by few users.

The flagship of the Samsung Galaxy S5 was a breakthrough. It was possible not only to unlock the smartphone using the fingerprint scanner, but also to log in to the PayPal payment system. Also, the scanner functionality could use third-party applications. But because of the fingerprint scanning method (lingering), the solution in the Samsung S5 was losing touch ID.

Due to the nature of the operating systems, Apple’s solution for protection against hacking by malware is more reliable.It should be said that in Android systems up to version 6 there was no native support for this authentication method, and only in Android Marshmallow Google introduced support for the fingerprint scanner directly into the system. In the new OS version, it is easier for developers to implement applications for working with the scanner, since it is enough to add support for system APIs. There is no need for vendors to create from scratch or adapt ready-made software solutions, often not of the best quality or low convenience.

At the moment, the fingerprint scanner module is no longer the privilege of the flagships of the leading players in the smartphone market. This fashion was picked up by almost all manufacturers, and the scanner began to appear even in budget models. Developers are experimenting with the placement of this module ("Home" button, on/off, under the main camera), with the software part and functionality.

But today I would not recommend using such a biometric protection system for payments, storage of important personal information. Proof of this are examples of hacking with the help of finger casts and Touch ID, and scanners on Android. Perhaps the development of an ultrasound scan will correct this problem. But as a method of unlocking the smartphone - to protect against excessive curiosity of third parties, the fingerprint scanner is perfect.

Thanks to all Administrator!

Related thread:
Calibrate Proximity sensor on Mi Max 3! Wоrk almost on all devices with Snapdragon!
[How it Works #1] Proximity and Light Sensors!


Number of participants 10 Experience +129 Pack Reason

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2019-04-18 01:14:11
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Super moderator

Katrix | from MI 6


Thanks for the information!
2019-04-18 01:16:12
Thanks for the awesome thread
2019-04-18 01:20:48

Beta Team-Global

@Biswajit | from Redmi Y1 Lite


thanks for information
2019-04-18 01:35:02

Thanks for sharing. very useful thread.
2019-04-18 02:15:21

Super moderator

AP1972 | from MI 8


Thanks for the information!
2019-04-18 02:35:26

Beta Team-Global

georan. | from Redmi Note 5 Pro


Good .. thanks for sharing
2019-04-24 04:51:04


ph.eliezer | from Redmi 5


Thanks for the information
2019-04-24 05:11:48
very detailed explanation! Thanks!
2019-04-24 05:13:03
great thread thanx
2019-04-24 05:13:38

Advanced Bunny

saqi albela | from Redmi Note 5A


thanks ..useful info
2019-04-24 05:14:35
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