Protecting a Door

[JamesyBHOY]

I have been reading various threads here about Picking Locks,It started to make me think,especially as i am frequently away for from the house for long periods.So i thought i would ask something a little differently.What about the safety and security of using a digital keypad lock,Which removes the use of lockpicks and keys,Would these locks be vulnerable to any kind of electronic attack.

Something like this

http://www.securityengineering.co.uk/DKM210.htm

Just curious,So for arguments sake,Say i have it fitted on my door,How would you guys try get around it to gain entry to the house,other than trying different combinations.

Thanks James..

[kld1648temp]

;)
There are ways. If the intruder had access to the lock, they could simply wipe the keypad clean, and return shortly after someone entered through that door, then they would brush the keys with talcum or some other powder that would stick to the oils in your skin, and see what keys were pressed. From there it is a matter of 'brute-force' trial and error. Another option would be to sit across the street with binoculars and just watch an authorized person punch away digits. Micro cameras are fairly common nowadays; an intruder could conceal one of these in a manner that it would view the keypad without the authorized user being aware of it, and if it could transmit, record the combo for access at a later time. For an out of the box idea, use a small audio recorder or transmitter to record/transmit the tones (beeps) the keypad makes. Provided the lock outputs different tones, it is just a matter of re-entering those recorded keys. The simplest way to get in, is to walk around the house looking for a door without the high-tech lock and picking it, or just break a window. I'm a newb though, what do I know.

[shrek]

There are a few problems problems with the methods you mentioned. Where I work there is a digital keypad, and when you want to enter the building you type in the combination. The numbers are randomly displayed on different buttons, so the talcum powder idea would not work... The numbers are also displayed VERY faintly, so faint that it would be very difficult for a camera to pick up the numbers, and that is if you could even get a view of the keypad. This same keypad also has an encloser around it so it can not been read except from almost directly infront of it.

Also the whole idea, like you see in the movies, of being able to open up the keypad and short the door lock mechanism also wouldn't work. The keypad is wired to a computer inside the building that does all the work. The keypad just displays and transmits the data to the computer, which in turn opens the door. All in all I would say the electronic doors can be very safe and it would be almost best to look for another entrance, or get violent :)

[Jacks Complete]

There are a few problems problems with the methods you mentioned. Where I work there is a digital keypad, and when you want to enter the building you type in the combination. The numbers are randomly displayed on different buttons, so the talcum powder idea would not work... The numbers are also displayed VERY faintly, so faint that it would be very difficult for a camera to pick up the numbers, and that is if you could even get a view of the keypad. This same keypad also has an encloser around it so it can not been read except from almost directly infront of it.
Where do you work? I haven't ever seen a lock like that, anywhere in the UK!

The highest security one I know of is a rotunda door with swipecard access. The floor weighs you, and stops the door after 1/6th of a turn, and calls security, if you are too heavy (i.e. two people going in). The bulletproof inch-thick glass is smoked, so you can't see through, there is no code override, you have to swipe both ways, and the windows all have thick bars as well. You could still get in by stealing a pass and using it quickly, though since everyone is known to everyone else, you would soon have problems. You also can't pass the pass back outside, as the doors open with the pass, but only cycle with the weight change, and the computer knows which side you are on. I have gotten past every other door and security system, but that one... Add to that the cameras, security guards, controlled site access and high fences, a solid brick exterior and 24 occupation and it is one tough nut to crack. It is the social network aspect that is hardest to overcome, though.

Digital locks are generally rated for a certain holding force, using an electromagnet. (Rotunda doors are a bit different) You could use a jack to force the door open, and a lot of systems won't detect it, as they simply don't expect the door to be opened without the magnet switching off. You can then shut the door and anyone who did come and look would see the door was shut and secure. Another way might be to use a powerful electromagnet to cancel out the one holding the door shut. Another way is to use a thin wire and trip the door release on the inside, if it has one.

I haven't ever tried any of these, I just use social engineering! :D Without extreme force and damn the consequences, you will never get inside (or back out of) the building I describe above.

[Hang-Man]

This is the guy’s house, not his weapons research facility. He is not going to be able to afford some crazy ass computer based keypad system etc. Just go buy a high security lock, it would provide far better security than a keypad of the same cost (hell, even 10X the cost). As far as some guy picking it; assuming you're home at night, and away during they day, the thief would have to pick your door mid-day. Which takes time, more so under pressure, and it is very suspicious. And if its someone breaking in while you're on vacation you're worried about, just throw a warded padlock on your door, your average thief, while he may be able to pick locks, wont be carrying the try-out keys he would need to pass a warded padlock. Finally, an expensive security system, suggests there is something worth guarding inside, so if you put obvious, keypad security on your door, you can bet someone will break a window and see what it is you're guarding. I personally don’t lock my doors. If you steal from me and live- you deserve whatever you stole. :D

[Jacks Complete]

Hang-man,

I would *so* wait till you were out...

I agree with what you are saying about the lock, though. Having said that, a lot of the time you see people with crazy hard locks on the front door, and nothing of note on the back door, and, I promise you, the door won't be as strong as the lock in 99% of cases. Either the door will break, and the lock pop out, or the door will bend and the lock bolt will disengage, or, most common, the frame of the door will fail, and the door will open that way.

Craziest door I know that I personally had anything to do with was a really neat one, in some ways. Weld some angle iron into a door frame shape, then weld a mild steel plate over the one side, then add mesh and concrete. Allow to set solid, then weld another sheet over the front!

This was for a swimming pool and health spa - you got a work out trying to get the door open, even when you had the "key"! It took four people to hang it on the rather strong hinges, and you wouldn't open it in an hour with a sledge-hammer, unless you knew how to use the hammer.

No visible keyholes, just a card slot and electric release.

How to get past it? There was an override with a screwdriver! The other way would have been to use a jack, and just jack it open. The electric part would have failed long before the door, the frame, or any other part of the system, as it was only rated to three tonnes (iirc) - easy for a small hydraulic ram.

Anyhow, my point is, there is always a weak spot - what do you define as secure?

[vulture]

Every security system can and will be beaten, just like tank armor.

The most efficient security is making sure that getting to your expensive/precious goodies costs time once someone bypassed security.

If your security system is fairly good, bypassing it will inevitably attract attention. That puts the thief under alot of time pressure. If they can't find what they're looking for within 10 minutes after detection, they'll be gone.

Leaving some easy bait (eg 20 bucks) helps distracting too. And ofcourse, non-lethal boobytraps. :D

Something shiny with a paint bomb attached to it will do wonders.

[nbk2000]

The strongest doors are the ones that don't swing open on hinges but slide aside within tracks in the walls.

If the door is strong, and the walls solid, then the lock becomes the weakest link, but that can be made very strong too. Plus, it's not something the SWAT pork would have much experience with, especially if you use RTPB "Smoke and Mirrors" to disguise it as a normal door. Thus, they'll attack it like it was, only without the expected results. :p

Also, depending on the design of the house, and the nature of the threat you anticipate defending against, you may wish to add a "Last stand" type of defense to your doorway...a rockfall.

I read about this in a design manual for nuclear weapons storage facility security from the '70s.

Basically, you have a large concrete slab supported by columns on one end, the other end sitting on a fixed support and the columns being weakened and explosive charges placed on the weak spots.

If attacked, the charges blow, and the slab falls down on one end, crushing the intruders and sealing the entrance, requiring additional attack time just to get to the door, let alone through it. :D

In this context, a small overhang to the entrance way is built, and topped with a pile of cinderblocks or such, with the supports being mechanically weakened so some means of breaking them is possible.

If attacked, the supports are knocked out, the overhang swings down over the doorway (which it so happens to just cover ;)), and the blocks fall on the intruders as they form a big pile in front of the door, impeding rescue of the crushed pork and any further attack on that door. :D

[Jacks Complete]

Nice idea!

Remember, the door should open outwards, as the cops use a hydraulic ram type device to push doors open very quickly and quietly. It expands into the frame, then uses that to push the door open.

With sliding doors, don't forget that they can still be made to jump off the tracks, in the same way that hinges will fail...

Personally I think the best system would be some kind of lift, or rotating cylinder. You can't do anything to it, as the harder you push the more stuck it gets! The distance is too far for the whole thing to be pushed through, and you are safe as anything will ever be. Also, once someone is inside, they are totally at your whim. Fill it with water, suck out the air, whatever.

Again, not very practical!

[vulture]

Let the intruders have the first, fake door. :D

Make sure it's hollow and filled with lachrymator, blistering agent or any other CW. ;)

Ofcourse, it has to look strong enough to provoke the destruction of said door...

[Ropik]

Safest doors are doors painted on concrete wall, but if you want to go home, it become a big problem.
Otherwise, as NBK mentioned, sliding doors with security lock. When you have standart doors, use methode invented by one of my friends - place a small steel girder(just big to fit snugly) into frame and fill spaces with concrete. This will probably hinder the ram-frame-widening-and-door-opening thing.

[xperk]

if discreetness of the door needing protection is not an issue - perhaps an effective countermeasure would be to restrain intruder movement in front of the door.
For instance by placing a cage outside the door increasing exposure time to the intruders. Or in other ways direct the would be intruders to attack the door at an unconvenient angle.

A way of directing intruder entry could be to place a concrete passageway in front of the door (for instance a large diameter concrete tube found at construction sites for sewers) - perhaps with an angle joint to further hamper the team strategies of intruders from covering each other or to move quickly. As well as keeping the kill zone out of sight from possible backup thus maximising the psychological effect. The tube doesn't need to be round it could be brick work or a metalclad wooden construction.

Such a tube could perhaps present an unpleasant ricochet property for anyone inhabitating it, thus diminishing the effect of the probable superior firepower of the scoundrels. While allowing the defender more economical use of offensive tactics from various prepared positions.

[nbk2000]

I just love how people keep bringing up ideas that I posted years ago. :)

[Jacks Complete]

I just love how people keep bringing up ideas that I posted years ago. :)
Indeed. And any study of ancient castles tells you that some of these ideas, they have been around for thousands of years! ;)

It was common for the multi-layer rings of defence that form a stone castle to make it very very hard for anyone to get to the gate without something getting dropped on their head from cover. Most "doors" were designed to get the crap kicked out of them, whilst the kickers took the usual casualties from arrows, etc. Once through, they would be in a nice stone tunnel, generally about 5 to 10 meters long, which sometimes turned sharply, such that battering rams wouldn't go round the bend (though this was rare, as it hindered the traffic of carts, etc. in times of peace) and which had handy trapdoors and slots through which arrows and boiling oil could be poured on the sods below, who came straight up against a second door, which was generally something like a steel portcullis, which, needless to say, allowed arrows and swords easy access. The attackers couldn't really shoot back effectively due to the burning oil, arrows, rocks, and, of course, the flailing and colliding of other attackers (how do you draw your bow when in a crushing mob? How do you fancy cutting through the piles of bodies of your friends to get to the gate for your turn to die?)

Anyways... back to more modern concerns. Earlier on, I posted about using a tyre instead of those rubber things. Well, I have got a tyre, but does anyone have a good way to cut the bastard thing? I thought bolt crops, but the rubber just gives, and nothing happens, plus they wouldn't cat in deeply. I then tried a set of lopping shears, which seemed to work fine. Then I saw the damage to the Teflon coated steel blades, and the utter lack of more than a mark on the tyre! No wonder they stop bullets!

I thought of a hacksaw, but it was so slow it was silly, so I got the jigsaw, and tried that. The smell! Burning rubber, alright! But it didn't seem to be cutting much, more sort of melting... so I stop, and check the blade, and find it no longer has teeth worth a damn! A new (wood) blade, gone in seconds. :mad:

I figure a steel cutting blade might do it, but it is going to be pretty slow, judging from the lack of impact from the hacksaw. Those little teeth just don't remove the rubber, more push it out the way.

Anyone know if there is some knack? I will cut it, I will wear a mask and cut it with my disc cutter if I need to, but it will stink.

All suggestions barring explosive ones welcome! I just don't want to break any more tools!

[nbk2000]

Use a carbide-grit covered blade for your jigsaw or, better yet, use a reciprocating saw with such a blade.

It's likely the kevlar or steel fibers in the rubber tire (radial reinforcment) that's fucking off your blades.

[Dave Angel]

If you have space in a big chest freezer perhaps taking the rubber down to -20C will make it easier to cut, though it would be even better if you have liquid nitrogen handy!

Another possibility, if you can stand the smell, could be to use a red hot section of resistance wire if you have a thick enough piece handy to stand up to the forces involved in the cutting.

Have you tried a nice new sharp stanley knife blade? Maybe go ask some delinquents what they use to slash tyres with!

[Edit] ah nbk's kevlar/steel fibres probably make my ideas useless!

[Jacks Complete]

NBK, good thinking. I will try my ceramic hacksaw blade. I know it is the steel wires, as you can see them quite clearly imprinted down the blade of my tree loppers! Sadly, the bolt croppers just won't cut them either, I think due to the rubber not cutting, but just being squeezed.

Dave, yes, the steel wires won't care about the redhot wire! It would work on Kevlar, though. Getting a cut in a tyre is easy, if you get between the radial bands. I, alas, need to cut through them.
Sadly, I don't have a supplier for LN2 anymore. :( That stuff is amazing fun!

Oh, forgot to say, I have some really big Torx head bolts, used for uPVC door frames. I plan to drive those through the rubber, to secure it, then I will try beating the crap out the door (well, not a door, but a set-up like a door) I drove one into a tree using a small driver bit and my socket set - they take some torque! (Hence the name, I guess)

Just realised, this-^ is in the wrong thread! (although it fits well here)

I also have the British Standards for locks now, as .pdf. I should really take a look at this new ftp: server and upload them. The specs are very high, like it must take more than 5 minutes and two blades to manually hacksaw the bolt off, etc. They should be of great interest to UK members!

[nbk2000]

Lock standards are of interest to anyone, regards of where they may live at at the moment, as people can get around, eh? ;)

BTW, rubber will transmit shock just fine, as it's used for backing EFP liners and such so they aren't spalled by the impact of the shockwave from the explosive, but rather deformed, so a door would still get the full force of an impact.

[Jacks Complete]

Lock standards are of interest to anyone, regards of where they may live at at the moment, as people can get around, eh? ;)
As can the locks! ;) I need to find some way to remove certain things from the pdfs first, however...

BTW, rubber will transmit shock just fine, as it's used for backing EFP liners and such so they aren't spalled by the impact of the shockwave from the explosive, but rather deformed, so a door would still get the full force of an impact.
I wasn't meaning the explosive shock, more the type of shock the door gets from a kick, etc., the kind the Anti-Piggy Door Ram Stopper you showed us a short time ago is designed for.
Why pay $15 (or ship them in from the states) only to find they are somthing you can make from old tyres?
Heck, mine will be even tougher due to the steel radial wires! Certainly bolt crop proof! :)

[nbk2000]

Shock doesn't care if it originates from an explosion or the impact of a sledgehammer, it's only a difference of time scale.

The anti-piggy rammer works because it gives a bit, to absorb some of the impact, then returns that energy back to close the door. Fiber reinforced tire rubber isn't going to stretch a bit, thus the impact would be fully transmitted into the target, defeating the purpose.

[Jacks Complete]

The shock is, technically, the same, but we both know that there is a critical timescale for it. Bullets cut holes through tin cans, if they are going fast, but travelling more slowly, they sometimes push the can over instead. If the material reacts on the timescale of the force event or faster, it will give and, perhaps, remain intact. I see a sledgehammer against a tyre as being a waste of time for the hammerer, as it will never be fast enough to beat it. Against an explosive/propellant, such as gunpowder, it will probably be quite a close thing, as a "fast" rubber can probably expand and contract at the same sort of rate as a slow BP. Against something that has a high VoD /brissance, the rubber at the site will have been destroyed before the rest has time to react.

I'm not so sure. Tyres do have give in them, otherwise why would they be rubber? They don't give much, true enough, but we don't want them to for this experiment.
Also, the radial bands are designed to stop the wheel stretching in only one axis, I see no reason why they shouldn't just spread apart a little if the rubber and bands are aligned just so.

Also, if that fails, I can still set it up so that the basic shape of the rubber tyre section acts to keep the door closed, but then flexes "open" and then closed again.

Think of the "U" shape. That will bend a long way, and bend right back, as a powerful spring, which is part of the design. A small section of that should do a great job, though it wouldn't look as good as a nice flat bit. Perhaps even just the natural curve radius of the tyres tread section will be enough.

Anyway, I am going to find out.

[nbk2000]

Never hurts to try, regardless.

BTW, tests were done on rubber tires used as perimeter barriers, where 10 pound charges of C-4 were placed on them, in an attempt to destroy them.

It failed to do so.

Why? Because rubber transmits shock, with minimal absorbing, to whatever it's in contact with, in this case the earth. So, unless the rubber is so cold as to be brittle, its elasticity will protect it from harm.

[Jacks Complete]

That bodes well.

I shall try very hard to find some daylight hours to get this project moved on this weekend.

Results asap.