[478] Vintage "Super Secret" Bulgarian Combination Lock

this is the lock-picking lawyer and what i have for you today is a really interesting 40 year old Bulgarian combination lock I was lucky enough to get this lock in its original packaging which has a combination of Bulgarian and English writing on it but you don't need to speak Bulgarian to figure out the model name for this lock we just sound out the Cyrillic letters and we find C pair secret this is our super secret combination lock so what we're going to do is take a look at what comes in the package here I'll show you how to open it how to change the combination and then we're going to take a look at the internals and see if we can find some flaws that we can take advantage of to open this up without the combination so let's dig in here in the packaging we of course get the lock and a handwritten tag with the factory combination and we have a set of instructions here written in Bulgarian thank goodness for Google Translate which lets you take a picture and Google will translate everything for you we have our instructions for changing the combination instructions for operating the lock and then a chart that we will need when we change the combination and we'll come back to that in a few minutes so first thing let's open this guy up we have nine eight four zero according to the instructions to open this up first you have to clear the lock by turning it clockwise three times then we stop on the first digit nine then we pass the first digit going the other direction stop on the second digit eight and we go directly to the third digit and then directly to the fourth digit and we should just slide right open now and of course it does to change this combination you have to open the back of the lock and that's done by putting the shackle in this position where the the flat portion is all behind them mechanism that allows us to slide this up and then we have to take the lock apart and we actually can't change the combination to anything we want there are five factory preset combinations and we can only use one of those five to change them we have to remove the entire wheel pack like this the instructions warn you to be very careful not to mess up the order of these discs and plates and then we look at the back of the dial and if we look carefully we try to zoom in for you we can see there are five numbers zero two four six and eight those five numbers are the last digit of the combination so from the factory it came with a zero we're going to change that to two and that's done by putting this little knot this little nub I guess from the disk into the number two position then we take this entire wheel pack reinsert it into the lock body and then put everything back together so I told you that the number that we set this on was the last digit so we now know our last digit is two but what does that mean for the rest of the combination and that's where this chart comes in we know that before the last digit was two and I'm sorry before the last digit was zero and so if the last digit was zero we check out this column so we know a nine when the last digit is zero turns into a 1 when the last digit is 2 and we have our 8 that turned into a 0 a 4 that turns into a 6 so our new combination should be 1 0 6 2 if you were paying close attention you may have noticed all we did was increase each of these numbers by two and that's actually what all five of the combinations are if we were to set the last digit to four then we'd be three two eight four then five four zero six and then seven six to eight I think so there's five possible combinations and they're all related all we have to do is increase each of the numbers by two so let's try then the new combination we just set 1 0 6 2 1 0 6 2 and I thought I might have messed that up and this 6 when I dialed let's try one more time 1 0 6 2 it slides right open now let's swap this back to the factory combination real quick once you know what to do changing the combination is actually very quick and easy on these okay and that should be nine eight four zero now okay now let's look for potential flaws in this mechanism that we might use to open this lock up now if we look at the wheel pack here we can see that each of the wheels has one true gate and to false gates now false gates are normally a very good thing for security they help it they help make a lock difficult to decode but in this case I notice that the depth of the true gate and false gates were very very close to each other also on each of these wheels the true gate and false gates are evenly distributed around the dial so I know this back wheel is for the number nine the first digit of the combination so because they're evenly distributed this is about a three and a six so I was wondering whether it was possible to open this lock up using the false gate positions so we're going to try to open this up we're not going to use the correct combination nine eight four zero we're going to try one of the false gates instead of nine we're going to use three so three eight four zero so three eight four zero as we can see that opened up and let's zoom in on this wheel pack we can see that the fence is in a false gate and you can actually do this with each of the first three digits in the combination so let's actually we tried three let's try the number six now and we're going to use false gates for the first three positions of the combination so instead of nine eight four zero we're going to try six four one zero six four one zero okay it's a little bit tight opening up but it does open up you'd expect a little bit of tightness when you're in three different false gates now the last position in here is a little bit different than the rest and let me show you why that is if we look at there we go the false gate on the wheel for the last digit you can see that it's actually being filled in by this little knob that's on the dial if you look at the false gate on the other side you can see that it's not being filled in so only one of the two false gates could potentially work however I'm not too concerned about finding shortcuts for that last wheel because we already know that it can only be an even number so we have at most five different numbers we have to go through so we're going to try something right now we're going to try to open this up using entirely false gates so instead of nine eight four zero we're going to try three one eight three I think [Music] okay it's a little bit tight again because all these false gates but as you can see it does open using 100% false gates so what does this mean for trying to defeat a lock like this well with respect to the first three digits of the combination because the true gate and false gates are evenly distributed around the wheel we know that you will only have to try four numbers in succession for instance one two three four before you hit a gate that will work and that's the case for each of the first four digits in the combination so to figure out a working combination for the first four digits you only need to try at most 64 different combinations then we go to the last digit and we know that can only be one of five so sixty-four times five is 384 and that's significantly lower than the 10,000 that it would look like the 10,000 possibilities it looks like this could have but it actually can be a lot lower than that for this reason because of the way these wheels pick up from one another the last digit has to be within half a dial turn of the third digit let me show you what I mean by that our combination is nine eight four zero so let's go nine eight four and I know that the last digit has to be between four and nine because if we turn any further then we'll mess up the disk for the third position and it just so happens that our last digit is zero and there's really only two possible combinations since we know it has to be even 0 and 2 and of course that opens up now let's say our third digit was 5 then we know that the fourth digit has to be 4 too ooh or zero so for half of the potential combinations there will be three combinations for the last digit and for half of the potential combinations there will be two possibilities for the last digit if you actually do the math on all of that that makes they're a hundred and sixty possible combinations that you would have to dial in before you're guaranteed and open and of course using the law of averages that means that on average you'll open this up with 80 tries so certainly not a quick way to open it but certainly there are also flaws that can be taken advantage of to open this lock up in any case I think it's a really interesting old padlock and certainly one I'm happy to have in my collection if you do have any questions or comments about it please put them below if you like this video and would like to see more like it please subscribe and as always have a nice day thank you

Channel: LockPickingLawyer

Views: 544,150

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Id: mnoKgAzacYI

Length: 12min 45sec (765 seconds)

Published: Fri May 26 2017