this kid i know just finds open locks in in our school and then he takes them home and pops them open with a screwdriver and just watches the internal parts. Easier, and you get free locks.

Dear all hackaday readers, i have created a little video that will show you how to open a master combinaison lock in about 2sec. What you need is a tool called a padlock shims avaiable on various lockpicking webshop like lockpickshop.com. Here it is: http://toad.datap0rt.info/x04d_masterlock.avi

The video has been encoded using the DivX video codec.

x04d

I hate to say this because I know someone is going to flame me for it and tell me I’m wrong.

I spent two years of high school trying to open “master locks”. I will guarantee that the pulling up on the locking mechanism (the U shaped thing) will not work on any of the Master Lock padlocks made in the last few years (I’m talking the trademark brand of master lock… not the cheapo ones).

This trick however will work fine on almost any of the cheapo ones that most people buy.

Anyway, if you don’t believe me then go try it on a master lock branded padlock.

As you can see in the video, the master lock that i used is quite new according to the teen colors. I think i’ve bought it last summer in a Wall-Mart. However, I know exactly what you mean: some masterlock seems unhackable using padlock shims and this is because they changed the mecanism a _little bit_. For those models, you just need to put the shims not directly on the retention mecanism because that will block for sure and probably broke the shims if you put to much pressure. You need to put the shim a little away from the middle, lift the shakle a little bit by shaking it up and down, and then move the shim slowly in the middle. It’ll slide itself under the retention mecanism and then you can lift the shackle without problem ^_^

I’ve passed some time studing locks, it required a lot of pratice ^_^

Does the shim thing work for the other kind of Master combination lock as well? The much sturdier looking kind, generally bronze-ish, with four 0-9 dials on the bottom?

does anyone know how to open those locks common in highschool locks where the lock is embedded into the locker and opens by sliding a metal piece sideways?

Bob,
My name is on it because I posted it, I post all of the features. You submitted it anonymously, did you want [thanks anonymous] at the end?

I really feel for the blog owners (eliot and vince) who have to put up with all this violence in their comments. I’m glad that the hackers I know in RL have social skills. Just because you’re on the internet doesn’t mean you have to treat everyone like shit.

Anyway, vince and eliot, keep up the good work, I think they really do appreciate it. I certainly do.

(oh, I was posting concerning bob’s lack of self control, not about you steve)

This definitely works, although your fingers will be tired from spinning the dial. I had a Master Lock which I didn’t have the combo too, stuck with it, and got it open this afternoon. It just takes a little bit of patience.

I’m suprised nobody has pointed out how old this is. I read about this on the Internet at least four years ago. It’s probably more like eight years, but I can’t remember.

Also, it’s not very useful. Going through up to 100 combinations “in the field” is not generally acceptable. And then there’s the fact that combination locks are rarely used for anything other than school and gym lockers. Real lock picking is much more useful.

So we have a video? this is a hack? where is the plans for the shim damnit!

Do you think any coders out there could make the “masterlock cracker” program into a java app? Just something that could be installed on a cell phone. That way, all you would have to do is figure out the last digit, open the program on your cell, and voila! It would be much more convenient than carrying a laptop around with the prog, or (dare i say) learning all of the math involved!

you can just buy a set of shims online

not too expensive

after reading this article, I was successful in using this trick to open a master lock. Very very cool, and not too difficult provided that you have patience.

This thread inspired me to write a CGI version of the app since the link to the VB app was unavailable and I saw some references to a web-based one at some university but it seems to be long gone as well. here it is, http://www.dfw.net/~scottvr/crackmaster/
There is also a link to the source.

Orphrey, any idea where to get a shim thin enough to fit in that tiny little space next to the dials on the brass locks?

Bob, how does one know before blowing a whole bunch of money on boltcutters whether they will be strong enough to cut the lock in question?

When I was a teen long, long ago, i figured out a different method to brute force master locks. it was easier then because they didn’t have the “dummy” notches cut in the drive wheel that this guy’s algorithm identifies — just pulling on the shackle while spinning would reveal the last digit.

The brute-force method is simple: don’t dial the whole digit space every time. first, i only used the numbers 2.5 apart, so I’d start with a first digit of 0, then 2.5, then 5, and so on around the dial until I got to 37.5. (masterlocks are made in great haste at low cost, so getting within a digit or so is usually close enough to open it.)

The important part i discovered was that by understanding how the “earlier” digit wheels are spun by the later digit wheels, I figured out that i didn’t have to go all the way back and redial all three digits every time. i’d dial the starting digit (usually zero) then go back all the way around a full turn, then stop at the first digit +2.5, and then back to the last digit. Rather than a two-full-spin reset, I simply went forward only to the first digit +5, then back to the last digit. I’d repeat, going back to +7.5, +10, etc., until the second digit was approaching the first at which point I had completely exhausted the first digit. I’d then spin the dial twice for a full reset of the inner dials, and change to the next first digit.

if i made a mistake, I’d simply spin the dial twice, starting with the same first digit but picking up the second digit where i had left off.

with not much practice, I was able to spin through two full first digits tests in about a minute, for a max of 20 minutes per lock. my average is probably about 10-15 minutes per lock (there are always a few screwups, and lost counts.)

Also, with the addition of the dummy detents found in the current crop of masterlocks i found i could no longer spin directly to the last digit. i had to stop at every little indentation in the last wheel and try the shackle at each point. my finger is usually pretty tired after testing all those combos.

a final note: once the lock is open (or if you simply encounter an open lock as a bonus), peer inside the lock with a flashlight. you can usually see the wheels inside the lock. take the opportunity to manipulate the lock until you’ve lined up all three notches by eyeball. make note of the combination you dialed (say you saw 10-32-24) now, add (or subtract, i can never remember which) about 10 to each number (yielding 20-2-34, note the wrap around the number 0). in any case the real combination will always be some fixed offset from your observed combination.

have fun!

the old master locks can be opened by kicking them, like on school lockers, hold it up so the back is facing you (it will be almost upside down) give it a good kick and it should pop open. it doesnt break the internals either.

I’ve made a couple of padlock shims, i’d shy away from soda cans – you’ll end up with a lot of cut fingers – very painful for your everday hacker to type with those cuts too! haha

a good metal i’ve found is the metal off of floppy disks (i’ve tested with a few lying around the office and “CH” have worked the best for me) If need be i’ll post a tutorial on making them. Beware that some floppy disks metal is weaker than others, and some is a *smigget* thicked than others. Mess around until you get a good one. Also these shims weaken over time and only work for about 3-5 padlocks… Becareful when using them so you don’t end up breaking it in the lock. This metal is also useful because it’s pre-rounded so you get less cuts :)

here’s an ascii diagram of what it looks like, first flatten it out…
_ _ _ _ _ _ _ _ _ _
| |
| |
| |
| _______ _______ |
|| | | ||
||_______| |_______||
|_ _ _ _ _ _ _ _ _ _|

Then you cut them up and you can make two… one for larger locks and one for smaller locks…

_ _ _ _ _ _ _ _ _ _
| |
| _ _ |
| / | | |
| _ _/ |_| _ _ _|
_
_ _ _ _| |_ _ _ _ _
|_ _ _ _ _ _ _ _ _ _|

The top one has worked best for me…

Shouting.

DIY padlock shims, with FLOPPY DISKS = perfect hackaday material, and helps for everyday hax0ring.

I liked the cell phone thing, but i m working on my calculator way.I have the (actually i rent it form school) those TI graphing calculator, it takes many stuffs even mario games , so i m trying to load this programme too.Just started the Scratch programming after understanding the logic of this stuff.I alwyas wanted to do this, after seeing those movies where people open thoses locks (Italian Job)
Thanks for this post….

20
bat to rear window is SO violent! then you still hafta climb or reach thru it. well… ya gotta do what ya gotta do – just check & make sure you werent sent written invitation first: can you see hinge pins? awfully “get smart”, wouldnt you say?

Sigh… this is like windows (or VAX…), why the hell are people still using it?

Well, why don’t you guy’s check out http://www.toool.nl/index-eng.php
and
http://connect.waag.org/toool/

They have some very nice videos and inforations about this.

ok…feel free to email me at rickysad@gmail.com

when i was in highschool…. 1985 or so a friend showed me how to read the serial number? on the back of a master lock, and there was this formula you could use…and with a very slight bit of trial/error you could open ANY standard (locker type) combination lock… i could open ANY master lock on any locker in my high school…. did anyone else ever run into this ????? it was amazing…. the TEACHERS would have me open locks of students who forgot their combos….

I think that just taking the whole entire lock apart with a pair of normal plyers (cat cut metal) and maybe a screw driver is much more fun, unless its ur own lock… I can take apart a lock in about 10-15 minutes…

I used to open the combo locks with a shoe string, rapping it twice around the dial and then pulling the shoestring up and down verying your strokes up and down till it opened! Anyone heard of opening them that way? It does work!

I could REALLY use your help!

My trusted Dudley lock, which I have used for over 10 years, seems to be stuck. The locking portion of the U seems to be stuck: it won’t pull up, and it won’t go back down into the rest of the lock. The dial won’t move, either… although if I jiggle the U, i can get it to move a little bit (sometimes).

Any ideas? I’d hate to get a new one, since I’ve used this same combinations forever!

Thanks,
Matt

hey i have the serial number for my lock, which is the ones they use at school in the locker rooms, its a masterlock with the u shape thing. can someone give me the combo?

ox4d yea the little clip on how to open a master combination lock in 2 sec. dosnt work so could you plz add a comment on how to open one in 2 sec. thnks

I have a Master Luggage lock that is stuck locked. I don’t remember the combination of THREE numbers to open the lock.
The #is: 468ODBLK.

Thank you to anyone who can tell me the easiest way to open this lock.

Hey, does anyone know the exact mathematical equations that are behind the generated 100 combinations? I’d like to program this on my calculator in Q-Basic and was wondering if anyone could help me out.

If you can, please email me the necessary math to injection@gmail.com

can sum1 explain the difference between the newer and older dial master lock latch bars…i just pent 15 min. trying to shim what i think is a newer model, cuz iv done it before fine

well i got a 40 number masterlock, i seen the video but i don’t understand it. can somebody please email me back to tell me how to crack it?? thx

hey i need the combo for a backpack lock model

Just so everyone knows, I bought two brand new masterlocks today, name brand with the black dial. Shim does not work, and I’m not suprised. Finding the 12 digit’s and eliminating 11 of them, then using modulo 4 to further get 100 combinations still works. I opened the new lock without looking at the combiniation in under 5 min. Then I opened another older lock my roomate had forgoton the combo for in about 8. (the combination was further down the list of possibilities that the first one.)
One thing to remember is that most locks are made to be exploited, so a locksmith can unlock them if need be.

I somehow set my 3 digit master lock incorrectly, so i too need to know a way to crack it. Marty, where can i get this video u are talking about?

http://www.geocities.com/masterunlocked/

I may have found a flaw in this entire hack. I just purchased a master lock, yes a true MASTER LOCK. The combination was 23-28-33.
If I’m not mistaken, and I have taken CALC 1250.
23 and 33 are not modualarly equivalent.

Does anyone have any clue whats going on.

That is odd. My best explanation is that the locks are not accurate down to the number. The algorithm would yield 21 and 25 (both of which are congruent to 33 mod 4), and it’s possible that 22 falls within the effective range – the room for error – of one of those values. Another consideration is that the given final value might not be quite right either – try to find the last value using the procedure as given, you might find it isn’t exactly 33. If it’s 35, for instance, that’s congruent to 23 mod 4. If it’s 34, then it’s congruent to 22 mod 4, and 22 could easily be in the same range as 23.

Anyhoo, that’s my best guess.

toni go all the way up the page and its a little text ill copy past it for ya : UPDATE: x04d sent in a video demo (DivX) of how to open a lock in 2 sec. using a padlock shim.

its under the small text on top

by the way my if u know how to open a lock please email me at : thadudeorama@gmail.com or
latreillemartin7@hotmail.com

Just bought two master locks today. One standard black, model 1500D combo 39-25-31. This one cracked by the book.

The other green, model 1529D combo 15-20-33 was difficult to find the last digit. I finally peeked and found the same problem that Chovy found. 33 mod 4 is 1 (33/4=8 rm 1), so the first digit combos should be: 1, 5, 9, 13, 17, 21, 25, 29, 33, 37. The actual first digit is not on the list. I tried using 13 and 17 with no luck. Maybe this trick only works with certain models?

As far as security is concerned, it’s not that hard to break open a combination lock, from what I remember. All you have to do is put a metal bar, preferably one that’s about the same thickness of the space of the shackle, inside the shackle and pull/push down. It breaks off quite easily.

I’ve found a way to open master #175 combo locks in less than 2 seconds using a very easy to make tool.
Also works on sesame combos…these type of padlocks look secure but are actually the easyest locks to open.
email me for info. zoome_1@yahoo.com

I have two Master combination locks that have unknown combinations. Can you help to break the lost codes for me to use the locks? Appreciate your input.

People, please send me the letter, how to open master locks or locks like Dudley, cause i forgot how to open my lock and i really need it to open it right now!! please hurry and send it plz~~!!

http://www.mydigitallife.info/2006/11/15/crack-and-hack-to-recover-combination-lock-or-master-lock-combination-instructions/ is a good site, satisfied many people >.> try it if u like.

Hey.. I work for a big machining company, and this one job we were doing, a company gave us a huge steel locker with a 0-99 combination on it. Is there any chance i can break this, or should i just get it drilled. Its been locked for about 2 years now and really just want to get inside lol.

we used to use this and shims to play pranks on ppl at school. but my school forces us to use master locks with a key hole in the back for a master key. so we made our own key from tearing it apart and looking at the pin heights. took a while to get it right but it works on every school lock.