Modular access system with fingerprint reader for an existing solid front door

[Greybeard]

Hello,
I am looking for a modular access system with a fingerprint reader for an existing solid wood front door.
Here is what I have in mind; I would appreciate tips or information from experienced users.

1. Fingerprint reader
Mounted on the exterior wall next to the door (surface-mounted or flush-mounted). The outdoor unit must NOT decode or store fingerprints; it should only transmit raw fingerprint data via cable to the controller unit INSIDE the house (NO wireless, Bluetooth, Wi-Fi, etc., to ensure safety from interception).
Must include "live detection" to prevent or hinder tampering.

2. Controller/decoder inside the house
Decodes the fingerprint data and sends the signal to open the motorized locking cylinder or motorized armored bolt on the front door. Wired connections only; NO wireless connections of any kind (to avoid easy tampering, eavesdropping, or hacking). Fingerprint enrollment only via authorization from the controller (ideally only via a key switch from inside the house). No authorization via PC, smartphone, smart home systems, Wi-Fi, etc.

3. Door hardware (interior side):
Motorized locking cylinder or motorized armored bolt (wired).

4. Emergency opening options (power failure or defective fingerprint reader)
Inside: Thumbturn
Outside: Locking cylinder with a high security rating

There are certainly standard solutions available for this—but I want a system without superfluous features that could create vulnerabilities (wireless connectivity, network connections, RFID, etc.).
Perhaps industrial solutions...

Can anyone provide relevant links or share their own experiences and tips?

[RoGeorge]

Action movies with spies and burglars show how fingerprints used as a door key is a bad idea.  Fingerprints can be harvested from almost any glossy object, or even worst, by cutting your finger! 

[Greybeard]

What about "liveness detection" (heartbeat, blood flow, etc.) or IR detection of deeper structures in the fingertip?
What is shown in action movies is often far away from reality.

[Greybeard]

Does no one have any info on this?

[BradC]

What about "liveness detection" (heartbeat, blood flow, etc.) or IR detection of deeper structures in the fingertip?
What is shown in action movies is often far away from reality.

In this case, not that far. A thin gel slipped over a real finger can defeat a surprising amount of the liveness detection, and as previously said that can be lifted from lots of surfaces. A decade or so ago I managed to lift a viable print off a fingerprint sensor on a laptop and use it to log into the same machine.

Anyway, there are plenty of biometric access control readers available. Most systems however don't enroll the print in the system to verify remotely, they verify it against the print template stored on an access control card. This turns a simple card into "Something you hold and something you are". Couple that with a PIN and you have the perfect trifecta "Something you hold, something you know and something you are". Alternatively cheap systems store it in the reader.

I'm sure if you look hard enough you'll find what you want. Whether it's at a price point that fits is another story entirely.

You can buy raw fingerprint sensors and their APIs are available. You may have just identified a gap in the homeowner market. Get soldering!

[RoGeorge]

There are plenty of ready made doorlock fingerprint systems:
https://duckduckgo.com/?t=ffab&q=doorlock+fingerprint+reader&ia=images&iax=images

And plenty of reviews/opinions, e.g.:  https://smarthomereview.org/best-fingerprint-door-lock/

However, using your fingerprints as a key is not a good idea, in the sense that it would not be secure.  A key has to be both unique AND secret in order to be secure.  Fingerprints might be unique, but they are not secret.

Biometrics in general, are not secret, you unintended display them publicly, whether you want it or not.

[grx]

Sending raw fingerprint data is an extremely bad idea regarding interception and replay, and is usually not how it's done.

What you want is a secure reader in which fingerprints are enrolled and only the match info is returned by the reader.

Which can also be intercepted, so usually you will want digital signatures and stuff to avoid forgery of positive matches.

that is quite a nightmare to design securely. Possible, but not easy.

[BradC]

]Which can also be intercepted, so usually you will want digital signatures and stuff to avoid forgery of positive matches.

that is quite a nightmare to design securely. Possible, but not easy.

Not really possible. One of the reasons I don't like Biometrics. You can change "what you hold" and you can change "what you know" but you can't change "what you are".

[grx]

Agreed, unless you have ultra stringent security requirements like an airport or a critical infrastructure, I would avoid biometrics and go with a card or just a numpad. Cheaper easier and less privacy risks.

[Greybeard]

How about a combination of a fingerprint reader and a passive RFID wristband, tag, or card?

[Benta]

Not really possible. One of the reasons I don't like Biometrics. You can change "what you hold" and you can change "what you know" but you can't change "what you are".

Most concise comment yet.   

[jc101]

Biometric readers are almost always linked to another form of identification, such as a username, smart card, or RFID tag, which becomes the index of the record you want to match. Without this index, the back end has to do an exhaustive check against a database of enrolled data. No two scans are perfectly alike, so achieving a high level of confidence in generating a match will be inconsistent. You might not get a match and be denied, or you might open up to the wrong person. All systems should ideally have at least three fingerprints per person, including one from the non-dominant hand. This mitigates cuts and the like. The image of the fingerprint never leaves the reader. Instead, the reader "reads" the image and sends a numerical representation of it for comparison. It isn't looking for an exact thing, like a password, but working to get a high confidence that what has been presented is good enough.

I've always liked randomised PIN pads. The pattern of the PIN is prevented from being looked at, and even the wear across the pad makes it very difficult to identify a PIN. I have fond memories of getting to grips with them in the past. We had 8-digit PIN numbers. Tapped my smart card against the reader and entered my PIN when it beeped. These days they can be implemented on a touch screen, making it a very cheap and effective entry solution.

If you need to uniquely identify someone, or revoke access to someone, everyone needs a unique PIN. Without an identifier such as a smart card, if someone tries to set a PIN and it's refused, it could be assumed it's someone else's. Handy info that. Using common PINs is never a good idea.

[RoGeorge]

Had a fingerprint reader once, long ago (the only drivers were for WinNT).  It was not very reliable, in the sense that sometimes you had to try 2-3, maybe 4 ti,es to get recognized.  That was slightly annoying, and definitely much, much slower than typing user.pass from a keyboard.  Even when it worked from the first time, it was still annoying to wait a few seconds to get access grant or denied.  That was a reader where you push the entire fingerprint against a small ellipse-like glossy surface.  It was also kind of picky relative to how well you position your finger (relative to the position of the finger when you trained the reader), and to the force you were pressing.

The second fingerprint reader I had was during WinXP, on a laptop with one of those blade-like fingerprints reader, where you have to "swipe" your fingertip on the reading edge of the sensor (the sensor looks like a horizontal line segment).  It was better/faster/more reliable than the old one, but still picky, and often you had to try 2-3 times to get in.  I can't tell you how frustrating it is to be denied 2-3 times in a row.  It was also pretty sensitive to how sweaty your fingertips were, and to the speed you were swiping.  It was fun at first, but actually never used it in practice, it was too annoying. 

Both the old and and the new reader were able to record more than one fingerprint, so losing one fingerprint integrity was not an issue.

Both were very sturdy in terms of false positives.  Since it was a new thing back then, showed it to everybody, but never ever managed to unlock the PC with an unregistered fingerprint.

[RoGeorge]

Forgot to say, the old reader was coming with a smart-card like a mobile SIM card, but full size, the size of a credit-card (no magnetic tape, just the chip).  Found a picture of that old WinNT reader, the smart card is the white thing already inserted.



It was using the LPT port for data.  A second connector was a PS/2 pass-through, connected at a keyboard/mouse port (not visible in this picture, the pass through connector happens to be underneath the reader).  The keyboard pass through was for power only, to feed +5V to the reader.

[Benta]

@jc101:
I like the randomised PIN pad a lot, never seen one in the wild, though. With a polarised filter or a visual screen around it, it's a great idea.

[RoGeorge]

I don't know by heart any of my pins.  I only remember the geometric figure they make.  A numpad with shuffled buttons would be game over! 

[jc101]

@jc101:
I like the randomised PIN pad a lot, never seen one in the wild, though. With a polarised filter or a visual screen around it, it's a great idea.

The ones I used you couldn’t see the number if you weren’t looking directly at them. It was well below the surface. You could watch someone put in a pattern, which was useless, but not the numbers.
Touch panel versions would need some kind restricted viewing film or a shroud.

Used them daily, you get used to them after a while. It’s a brain ache to start though. It’s so simple to implement I don’t know why it used used more often.

Edited to fix typo.

[Benta]

The ones I used you couldn’t see the number if you were looking directly at them.

Should be weren't, I think. Still great.

[jc101]

The ones I used you couldn’t see the number if you were looking directly at them.

Should be weren't, I think. Still great.

Fixed, thanks.