How to allow multiple finger print for authentication using fprint_demo

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sobuj53
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How to allow multiple finger print for authentication using fprint_demo

Post by sobuj53 » Wed Oct 09, 2019 3:21 pm

Hello,
I have a finger print enabled laptop and relying on fprint_demo for finger print authentication. But for authentication it only asks for a selected finger to be swiped, (in this case it's left middle finger)

Image

though I've multiple finger print enrolled.

Image

I was wondering if it's possible to pass authentication using any enrolled finger print. The reason I'm asking this, as sometimes my finger print scanner fails to identify the asked fingerprint for authentication but, if I enroll my same finger's print multiple time and if authenticator accepts any enrolled fingerprint then my authentication success rate will increase dramatically. I'd really appreciate if anyone can help me on this or give me any insight how it could be achieved.

Thank you,
Sobuj
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secureIT
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Re: How to allow multiple finger print for authentication using fprint_demo

Post by secureIT » Sat Oct 12, 2019 12:29 pm

May be your handling of the fp-reader by enrolling the prints is not the same as by identyfying on log in.
The prints has to be enrolled by slowly swiping the top of the finger up and down vertically and also by rolling the top of the finger horizontally left to right.
Same to try, when log in....

May i ask you for the System and Desktop you are on ?
In der Ruhe liegt die Kraft ! .......... The strenght is to be found in serenity !

sobuj53
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Re: How to allow multiple finger print for authentication using fprint_demo

Post by sobuj53 » Sat Oct 12, 2019 12:50 pm

Thank you for your reply.
I'm on Linux mint 19.2 cinnamon.
What you are saying is not the case. The problem is, I've a very sweaty hand and my finger sweats a lot :( . That's why my FP reader sometimes has trouble identifying my FP even though I've enrolled it. My goal is to enroll same FP multiple time (which is possible at this time) and make pass authentication using any of the enrolled FP. But seems like fprint_demo doesn't permit this behavior, I can only pass authentication by swiping the asked finger in the screen.
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secureIT
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Re: How to allow multiple finger print for authentication using fprint_demo

Post by secureIT » Sun Oct 13, 2019 2:40 pm

The system will ask for the fingerprint that it finds first.
So it does not seem possible to use all fingerprints because they are not requested for authentication at the same time..
For solving your Problem simply use only one fingerprint for authentification and delete all the others.
I think it's easier to just dry a sweaty finger than the whole hand.
The index finger may be the right choice, because it's the one most used with the pad or the mouse anyway, and it's not that humid.

By the way ..... please tell me, if you really can login by using LM 19.2 Cinnamon (because we assumed in another thread for this fp-reader (not in this forum) that lightdm was the reason why no fingerprint was requested for authentication at login)

And one more request: if so, I would be grateful if you could detail the steps (what exactly did you install from where in which order, and what adjustments did you make in the system-files ? ) that led to the solution.
Either here in this thread, or you could also make a tutorial from it.
Thank you so much :)
In der Ruhe liegt die Kraft ! .......... The strenght is to be found in serenity !

sobuj53
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Re: How to allow multiple finger print for authentication using fprint_demo

Post by sobuj53 » Sun Oct 13, 2019 11:48 pm

Thank you for your reply.
So it does not seem possible to use all fingerprints because they are not requested for authentication at the same time..
Well it doesn't have to be that way. It can always try to match the swiped fingerprint form its already enrolled fingerprint database. This way no matter which fingerprint is swiped it's possible to find a match if that fingerprint is already enrolled to the fingerprint database.
please tell me, if you really can login by using LM 19.2 Cinnamon
Yes I can use it to login. However Need to click the switch user button (the button which shows 2 heads) then it'll ask for my fingerprint first, if it's not correct then it'll fall back to password prompt.
what exactly did you install from where in which order
Well I already have made a kind of tutorial for this :D. You can take a look at my 5th post of this thread. Though I should say this tutorial is Validity Fingerprint sensor device (138a:003f) VFS495 specific. But I'm sure that, you'll find your device specific tutorial if your device is not Validity Fingerprint sensor device (138a:003f) VFS495. However the most important file that actually defines which authentication method will take the lead is /etc/pam.d/common-auth. It'll have to look similar like this. Be advised this a very dangerous file to play with, if you do something wrong you'll not be able to log in. So please setup your SU password before you proceed, so that you can make changes to this file from recovery if you mess up something. I've been there and the experience is far from pleasing :D .

As for now I'm actually using Windows Hello™ style facial authentication for Linux in combination with Fingerprint and password. I have set it up in such way so that my face is used for primary authentication, if it fails fingerprint is need, if that fails too password will be used. it's really convenient if you don't mind using your webcam. Here is what my /etc/pam.d/common-auth file looks like.
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kuehhe1
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Re: How to allow multiple finger print for authentication using fprint_demo

Post by kuehhe1 » Wed Oct 16, 2019 2:38 pm

Hello @ sobuj53,
sorry for my bumpy start, I have moved my questions there:
viewtopic.php?p=1702248#p1702248

Unfortunately, I can not delete my sums yet.

Best Regards
kuehhe1
Last edited by kuehhe1 on Thu Oct 17, 2019 1:59 am, edited 2 times in total.
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sobuj53
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Re: How to allow multiple finger print for authentication using fprint_demo

Post by sobuj53 » Wed Oct 16, 2019 4:02 pm

@kuehhe1, This thread is not meant for finger print login tutorial. Please post your question in my other thread (FP login). I'll try to answer your question in best of my ability.
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