How does the biometric fingerprint scanner work

Biometric fingerprint scanner: A quick alternative to the PIN

PINs for your own SIM card, smartphone, PC and of course the current account. Who can still keep track of this? With the fingerprint scanner, cell phone manufacturers have long been supplying an alternative to the short number codes and the banks are following suit with their mobile apps. We reveal everything you need to know about fingerprint scanners.

PIN numbers are an everyday security standard. Every consumer has several such numbers in his head. When the half dozen slowly gets full, the whole thing quickly becomes confusing. Anyone who always uses the same pin code is exposing themselves to a high security risk. Lots of apps too, especially for Mobile banking, rely on PINs, but with the biometric fingerprint scanner they offer a quick alternative that does not take up any memory. But is it also safe? We clarify.

The most important things at a glance

  • Best compromise
  • Compared to other login methods, the fingerprint sensor offers the best compromise between security, convenience and speed. The increased convenience is particularly noticeable when mobile apps for online banking close quickly and require repeated login.

  • Two procedures
  • There are two types of fingerprint scanner: optical and capacitive. Its simple construction is at the same time the strength and weakness of the optical scanner, because the comparatively simple construction is also easier to outsmart, which is why the capacitive method is primarily used.

  • Broad support for banking apps
  • Almost all common banking apps offer the option of using the fingerprint sensor as a replacement for confirming the TAN. In this way, depending on the type of smartphone, you can make transfers with Touch ID or fingerprint or open the app whenever a PIN has been entered beforehand.

  • Many smartphones have a fingerprint scanner
  • Nowadays, mid-range telephones are already equipped with a biometric fingerprint scanner. We have listed a small selection of smartphones that have the component at the end of the article.

Login procedure for mobile banking: The best solution for the fingerprint scanner

Banks use different login methods for their mobile apps: depending on the bank, passwords, PIN codes or registration via biometric fingerprint are required. In some cases, it is even possible to register using the TAN generator. The overview below is intended to show the advantages and disadvantages of each of these options. It also contains some examples of where the procedures apply.

In terms of speed and convenience, the biometric fingerprint sensor depends on both passwords and PIN codes. ChipTANs as a login procedure are very secure and enable transactions on the smartphone, but they also require a second device that you do not always have with you.

In terms of security, the biometric fingerprint is at least on the same level as the classic code process. You can read about safety information further down in the article.

The only downer with fingerprint sensors is that they are already installed in many, but not yet in every smartphone. That's why we've put together a list of smartphones that have a fingerprint sensor.

Secure apps with touch ID and fingerprint

Apple is considered a pioneer in the field of fingerprint scanners and brought the biometric scan for the first time with the iPhone 5s from 2013 in a smartphone under. Since then, most of the manufacturer's models have the function under the name Touch ID is known.

In the meantime, other cell phone manufacturers have long since followed suit and built their own fingerprint scanners. On Android, the function generally exists under the name fingerprint.

Apple is a pioneer among smartphone manufacturers when it comes to fingerprint scanning (image source: © NeiFo /

Activate Touch ID on the iPhone

Before Touch-ID can be used to secure and unlock apps, the function must of course be switched on. This is under "Settings> Touch ID & Code" possible. The very first setup must also include the fingerprint. If you are already using Touch ID to unlock your smartphone, you can of course skip this step.

Activate fingerprint on the Android smartphone

Since devices from many different manufacturers run on Google's Android, the setup of the fingerprint function is not entirely uniform. But the first address should always be that Settings menu be.

The following variants are known to us:

  • Menu> Settings> Biometrics & Security> Fingerprint Scanner
  • Menu> Settings> Biometrics & Security> Fingerprints
  • Menu> Settings> Finger scanner> Fingerprint manager
  • Menu> Settings> Device security> Fingerprints
  • Menu> Settings> Device Security> Fingerprint Scanner

If none of the named menu paths exist on your smartphone, it is best to contact the manufacturer or suggest calling up the function in User manual to.

Banking apps that support touch ID / fingerprint

The nationwide support of the fingerprint scanner stands in the way that not all providers support biometric unlocking. Mobile banking apps but are already very far in this regard and, to a certain extent, are taking on a pioneering role. You can use fingerprints to Transactions partially confirm in a flash. Other banks continue to use the TAN for transfers, but the fingerprint can at least be used to log in.

These banking apps support Touch-ID / Fingerprint:

  • ING's banking to go (login and transfer)
  • DKB banking app (login)
  • 1822moblie from 1822direct (transfer)
  • Comdirect mobile app (login)
  • N26 mobile app (login)
  • Postbank mobile banking app (transfer)
  • SecurePlus from Consorsbank (login)

Other apps that support Touch-ID / Fingerprint:
Of course, the use of the fingerprint scanner is not limited to banking apps. A few other apps are listed below in which Touch-ID or fingerprints can be used.

  • Dropbox
  • Notes (iOS system app)
  • 1Password
  • Evernote Premium
  • Amazon
  • PayPal
  • Google websites (Android)

Activate log-in via fingerprint with different providers

Activate DKP app fingerprint
You use the fingerprint function of the smartphone in the DKB app with the help of a device link. Open the DKB banking app on your mobile device and log in. You will then be asked if you have saved your current mobile device as a trusted device want to store what you have to confirm by TAN. Now the DKB app can be opened and used at any time with a finger scan.
Activate the Sparkassen app fingerprint
At the Sparkasse you have to use the "S Identity" app to log in with your fingerprint. Here you choose a 4-digit PIN so that you have access even if you have any problems with your fingerprint. If your smartphone has a fingerprint scanner, you will then be invited to use it.
Activate ING app fingerprint
With the ING app, you can easily activate in the settings that the fingerprint should be used for logging in.
Activate Comdirect app fingerprint
With the Comdirect banking app, too, log-in can be easily activated in the settings using “fingerprint”, as it is called here.
With the N26, you can activate the fingerprint function in the settings immediately after logging in for the first time. Here the option is called "Touch ID"

Fingerprint scanners in apps: unthinkable a few years ago

Flashback: We're going back to 2009. At that time, the iPhone 3g was still filling the shelves of cell phone shops, and a fingerprint scanner in apps was out of the question. According to a majority of the experts, it should at least be 5-10 years take time until the so-called biometrics, for example iris or fingerprint scanners, are used across the board. The same graphic can also be seen that a not to be despised part of the experts must have been of the opinion at the time that the biometric fingerprint scanner would work No way really prevail.

Today we know that these ladies and gentlemen were probably wrong. Biometric scans may not be ubiquitous yet, but the technical requirements for something to change have been more than met. So it's high time to report on the sense and purpose of the smartphone's fingerprint scanner.

How does the fingerprint scan work?

A distinction is made depending on the design of the scanner two different methods of the fingerprint scan: the optical and the capacitive.

© 422737 /

The optical scan with light
In the case of the optical fingerprint scanner, there is a below the support surface charge coupled sensor. The component will CCD and is also used in digital cameras. The CCD essentially consists of light-sensitive diodes and its own light source.

During the scan, the different areas of the finger are illuminated to different degrees. Papillary ridges - the individual finger grooves, which are unique to each person - appear darker than the spaces in between. The analog image that emerges becomes one digital pattern converted and saved. With each scan, the new image is then compared with the pattern.

The capacitive scan with electric charge
There is a Silicon layer, including a network of a large number of Capacitor cells. When placing the finger the electrical charge changes in the layer - but only where the papillary cells rest. The charge remains the same in the gaps. An analog image is created again, which is converted into a digital pattern by means of a converter and saved.

In the meantime, the capacitive fingerprint scanner has established itself. Although its construction is more complex than that of an optical scanner, it is also easier to outsmart. This could be done, for example, with a high-resolution image of the fingerprint, which does not work with a capacitive solution.

By the way: Most fingerprint scanners these days also distinguish whether the scan is living or dead tissue. Be for it Infrared sensors used. Living tissue reflects infrared radiation, while dead tissue absorbs it.

How secure is the fingerprint sensor?

With all the convenience, the question of the unlock method is always one of the security. It should always be in the foreground, especially when it comes to sensitive data - which is clearly the case with financial data.

The fact is: New technologies are always vulnerable at first. But it is also a fact that the processes behind the biometric fingerprint scan are no longer that new. Industry has made its mistakes when it comes to safety and has learned from them accordingly. The recognition of the fingerprint is still not entirely undisputed, which is the reason why the scan is still carried out with a second hedge is coupled. Most of the time it is a PIN number or a password: If the decryption with the aid of the fingerprint was not successful, the classic methods come into effect.

However, this is more like a Additional benefit for the user as a security barrier, because whoever has successfully copied a fingerprint once, avoids the second query at the same time. Because of this, the scanners themselves have also become smarter. We have already reported elsewhere on infrared sensors that distinguish living from dead tissue. However, the storage of the stored fingerprints has also improved and is a complex process encrypted. This makes it very difficult for third parties to access the stored samples. Since stored passwords are usually also encrypted on the phone, fingerprint scanner and PIN code are probably at the same level of security these days.

Useful information: On the HTC One Max (2013) and the Samsung Galaxy S5 (2014) were saved images of the fingerprint as bmp file deposited. So it was an image that at that time could be read out over the phone without any major fuss. The problem was subsequently corrected with a patch.

What happens if the smartphone is lost?

Losing your smartphone is annoying anyway. But what to do if the device is also the gateway to online banking because it has been secured with your own fingerprint? First things first: don't panic. The great strength of the biometric fingerprint lies in its uniqueness. If the device gets into unauthorized hands, the fingerprint scanner protects you from misuse. The combination of fingerprint and online banking is by no means necessarily a bad one!

Of course, you still have to take action as soon as possible. What exactly to do depends on your bank. In no case can it hurt to contact them and report the loss of the phone, provided you are using it for mobile banking. Normally, you will then receive instructions on how to deal with the loss of your smartphone.

Most banks use this to set up their banking app iTAN procedure. You then need one or more numbers from a valid iTAN list. This often also applies when transferring the app to another device. Once the app has been set up on a new phone, you can block a smartphone that is no longer in use for access to mobile banking. In other cases (e.g. at the DKB) the re-authorization is only by letter possible.

Reading tip: Do you use contactless payments with your bank card? Find out here how you can deactivate contactless payments for your security.

Cell phones with fingerprint scanners

The fingerprint sensor is no longer an exclusive feature of expensive premium smartphones, but in the Middle class arrived. We are therefore introducing you to some devices from various manufacturers and price categories that have a fingerprint scanner.

Cell phone without a fingerprint scanner

If you still have a stomachache at the thought of a fingerprint scanner, you don't have to do without a modern cell phone. Here is a list of smartphones without fingerprint scanners:

- 6.1 "Liquid Retina HD LCD display
- IP 68 water and dust protection
- 12 megapixel two-camera system
- 12 megapixel TrueDepth front camera
- Face ID for secure authentication and Apple Pay
- A13 Bionic Chip with 3rd Generation Neural Engine
- Wireless charging
- 5.93 "HD + display
- Android 8.1, 1, 4 GHz octa-core processor
- 32 GB storage capacity, expandable with MicroSD card (128 GB)
- 12 MP main camera, 5 MP front camera, 1080P video recording
- 3 GB of RAM
- 5.7 "Flexible OLED with FHD + and 444 ppi
- Processor: Qualcomm Snapdragon 855
- Main camera: 16 MP + 12.2 MP
- Front camera: 8 MP
- 6 GB of RAM

What one should also mention here, however, is that the function can of course also easily be deactivated on practically all devices.

The fingerprint sensor is an alternative to PINs and passwords that has its authorization. Banks recognized this as one of the first industries and have come a long way with fingerprint support coverage. So not only can you unlock your phone with your fingerprint, you can even confirm financial transactions.

The advantages are obvious in the truest sense of the word - you always have your fingerprint with you and it is guaranteed to be unique!

Further articles that may also be of interest to you:

How does NFC work?

Apple Pay Germany

Current account comparison of all free providers

Many thanks to © ar130408 ​​/ for the cover picture!

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This entry was published on by the editorial staff under Statistics & Interesting Facts.