Many people use the key lock boxes manufactured by the Supra lock box company. This is a metal box, usually fixed to the wall by the front door, with 10 buttons on the front which you press to enter the secret combination.

**Isn’t this an odd article for Bug Advisor?**

This article began when we arived at our rental villa in Florida and realised that we’d forgotten the lock box code. I sat in the rental car, running the air con, wondering how many possible combinations would it take for me to open the box. After a long flight, my girlfriend just wanted me to call the management company and ask for the code – writing down a sequence of possible numbers didn’t make me very popular. So no bugs but travel was involved.

**History**

Oregon real estate agent, Delbert Williams, was annoyed by the amount of time it took to chase down keys of listed properties in the busy post-war real estate market of the early 1950s. His frustration compelled him to invent a secure key holder which combined a sand-casted metal container and a Yale bicycle lock.

The success of this product (which became the predecessor of the current day portable key box and eventually led to the development of the pushbutton lock) resulted in his forming Supra Products in 1955. Supra continued as a family managed company until 2002, when it was acquired by GE Security, a division of the General Electric Company.

**Current Usage**

Nowadays, the usage has extended to homeowners who want to keep a spare key somewhere different than under a doormat or flowerpot and holiday villa rentals.

**Video**

There is a video on how to open and close a lockbox on YouTube – not sure why a video was needed but if you’ve never seen one in action then now is your chance!

**Setting the Combination**

The inside of the lock box lid has a cover which, when opened, exposes 10 screws corresponding to the numbered buttons on the keypad. The screws have arrows on them. A combination is set (or reset) by changing the direction of the arrows for numbers in the combination.

**How secure are these boxes?**

Well you probably think that the four-digit combination can be any number from 0000 to 9999. If it really was 9999 combinations that would be pretty good, as anyone attempting to gain entry to the lockbox, then the property, would have to spend quite a while pressing buttons and pulling on the metal cover – the whole mechanism is quite clunky and even when you know the combination the cover doesn’t always come off.

Sadly the combination can’t be 0000 as the setting inside the lock box lid only allows for one number between 0 and 9 to form part of the combination. So the first possible number is 0123. I guess you’re thinking, well that’s still a lot of numbers to try, even though you can skip 0131 as it has two 1s in it.

Unfortunately there is another design flaw in these boxes: The setting inside the lock box lid doesn’t allow you to choose the order in which the numbers should be entered. That means that if you tried 0123 then there is no need to try 1230, 2301, 3210 etc.

I sat and worked out the possible combinations for a lock box and there are only 161. I won’t publish the list here as it might fall into the wrong hands.

**9th August update **– I now have a formula to work out combinations and wrote about this in a newer post here.

**So what should you do?**

I’d recommend changing your lockbox to something more secure. I haven’t researched better options, but if there was something with six rows of rotating combination wheels, where each number could be anything, then I’d buy that. At least then you really would have a range of 000000 to 999999.

**And what will I do?**

I’m going to write to the lock box company and tell them my findings. My guess is that they already know, but keep selling the boxes anyway.

Stephen8

said:How secure are these boxes?

I counted 210 combinations – not that it makes a big difference in the scheme of things.

bugadvisor

said:I still think it is 161. But even at 210 that wouldn’t take too long to open.

Bud Mor

said:It is not 161. It is 210. It is (10 x 9 x 8 x 7) / (1 x 2 x 3 x 4). But actually there are more as you don’t have to use a 4-digit combination. You can use any number. So there are actually 1,023 combinations; although I doubt too many people would use a 1, 2, 7, 8, 9 or 10-digit combination. But that would still leave 792 useful combinations.

anbudmor

said:It is not 161. It is 210. It is (10 x 9 x 8 x 7) / (1 x 2 x 3 x 4). But actually there are more as you don’t have to use a 4-digit combination. You can use any number. So there are actually 1,023 combinations; although I doubt too many people would use a 1, 2, 7, 8, 9 or 10-digit combination. But that would still leaves 792 useful combinations.

Mike

said:You have no idea what your talking about, a 4 digit code that uses numbers from 0-9 would have 9,999 different combinations.

bugadvisor

said:You obviously didn’t read the article properly- only one number can be set as part of the combination – so no 0000 nor 9999

A. Hill

said:The math is only a concern if you don’t wish to damage the lock box. Several months ago, I drove an hour to show one of our warehouses to a potential tenant. When I arrived, about 5 minutes early, I realized that I did not have the lock box combination and was going to be unable to get the potential tenant through the 70,000 square foot space. What a complete loser…

I got a portable drill out of my SUV, loaded a 3/8 drill bit and proceeded to drill downward (just above the Supra’s top center button) between the lift out face and the lock box itself. In about 20 seconds the lift out face with the 10 numerals on it was breached and fell out in my hand. I took out the door key and unlocked the warehouse.

Frankly, I was shocked at how easy the lock box was to get open…unfortunately both the lock box and the cover plate were destroyed in the process. They will only keep the “honest” people out. I currently have several of the Supra boxes in our offices but we do not remember the combinations. We simply use them as paper weights…

Wilson Abello

said:Hello!… I too have one of those GE Bo codexes with a forgotten code… Could you please help me?

THANK YOU!

bugadvisor

said:Wilson – well to help you I’d have to send you the list of 161 possible combinations. But as I said in my post, I don’t really want to do that.

Howard Courtney

said:wilson… I can not find my combination… can you send me your list of 161 possibilities and I’ll try it! hdcourtney@gmail.com

bugadvisor

said:Please send me a picture of you lockbox paul@feagan.com

Peter

said:Hello bugadvisor, I have a supra box at my front door been locked probably for years.

I recently started renting this place and it is anoying having that box there I cannot open and use it. I do not like to try cutting off the box because I might damage the door. Could you please send to mee the list of combinations or give me a clue how to work out myself? I will appreciate very much. Thanks. Pete

bugadvisor

said:Hi Peter, much as I would like to send you the list of possible combinations, I can’t do that as the information could fall into the wrong hands.

As this is your own front door and you already have the keys, it shouldn’t take long for you to enter as many combinations as you need to gain access to the box.

John Coleman

said:Just remove the door’s lockset. Then look to see if the handle/knob can be removed. If not, buy another lockset and re-key it.

Mike

said:are you guys retarded? There are NOT 161 combinations, there are 9,999 combinations.

bugadvisor

said:No 0000 nor 9999 as only one number can be set

Howard Courtney

said:I still haven’t been able to find a complete list of actual numbers to try

Howard Courtney

On Wed, Mar 15, 2017 at 2:21 PM, bugadvisor.com wrote:

> bugadvisor commented: “No 0000 nor 9999 as only one number can be set” >

bugadvisor

said:I can send you a list – just email me a picture of your lock box by an open door

Michelle

said:I use 5 numbers when I set my combination so I’m thinking mine is more secure. How many possible combinations is it for 5 numbers?

bugadvisor

said:Michelle

I’ll try and work out the combinations and let you know. But my instinct at the moment is that 5 numbers might even be less secure than 4. For example, if you chose any 10 number combination, the only number you would need to open the box would be 0 1 2 3 4 5 6 7 8 9 0.

For a 5 number combination, the first valid number is 0 1 2 3 4 5

anbudmor

said:For 5-digits there are 252 combinations. (10 x 9 x 8 x 7 x 6) / (1 x 2 x 3 x 4 x 5)

bugadvisor

said:Michelle – well I had a quick count and I think only 122 combinations so less secure than 4 numbers (161 combinations). But I’ll need to check properly at the weekend in case I missed any combinations. The only good news is that the boxes are more secure if people don’t know how many numbers they need to enter. So if I’m trying to get into a box, I’d need to enter 161 combinations of 4 digits, then 122 combinations of 5 digits plus other combinations of other digits that I haven’t worked out yet!

Pete

said:why you need to count? there is a simple formula which gives you the exact number of combinations

bugadvisor

said:Pete

I’m counting because I don’t know the simple formula and didn’t try and create one!

Feel free to share the formula as long as it only provides the possible combinations for 4, 5 etc entries, rather than a list of entries.

You can also email me on paul@bugadvisor.com

Paul

ahg

said:…I’d need to enter 161 combinations of 4 digits, then 122 combinations of 5 digit…Unnecessary. Another design flaw is that the button to open the box doesn’t also clear it. Assuming most people will choose combinations of 3-5 digits, you can try three combinations in one sequence without having to start over – reducing the overall effort required to cycle through all combinations.

e.g. If the combo was 1-2-3-4-5, you could enter 1-2-3, try to open it, then press 4, try to open it, and then press 5 and it would still open the lock. That’s three combinations with only having to press 5 buttons, instead of 3+4+5=12 buttons if the open latch also cleared it.

Jacob

said:If didn’t already know you can choose how many different numbers you want, between a 3 number combo and a 7 number combo. I would imagine this would leave you with several thousand different combos to try out before you found the right one

richard

said:The number of combinations is 1024

that’s because each button can be either pressed or not, order doesn’t matter,

that’s 2 possibilities for each button

2*2*2*2…*2

=2^10

=1024

of course some of those (no buttons pressed, 1 button pressed etc) are not good combinations to use but it’s still about 1000 combinations

In the end none of that matters. These locks are vulnerable to manipulation exactly like the cheap combination luggage locks. If you know what you’re doing you can open them in a minute easy.

The three letter dial type locks are a lot more secure, I recommend those (They’re harder to manipulate)

Aneirin

said:Sorry, but 1024 is way out of line. The true number of combinations (order agnostic) is 210 for 4 and 6 digits, and 262 for 5 digits. How do I know this? The combination formula is (n!)/((n-r)! * (r!)) where n is the number of buttons you have (10) and r is the number of buttons needed to press. There’s also no point to hiding the list because many math websites that has the combination formula will also spit out a complete list of all combinations.

bugadvisor

said:Thanks Aneirin that’s exactly the formula I was looking for. I’m still not sure how I only got to 161 when working out the list longhand, but the proof of the formula is easy when r= 1, i.e only one number to choose from:

10! = 3,628,800

(10 – 1)! = 362,880

(1!) = 1

so (10 – 1)! x (1!) = 362,880

and 3,628,800 / 362,880 = 10 key presses

I’m going to re-blog this with some explanations and figures based on your formula.

Say if I don’t know the value of r, is the total number of combinations 10 + 45 + 120 + 210 + 252 + 210 + 120 + 45 + 10?

anbudmor

said:No it is 10 + 45 + 120 + 210 + 252 + 210 + 120 + 45 + 10 + 1. The last 1 is for a 10-digit combination.

bugadvisor

said:Reblogged this on and commented:

I’m re-blogging with new math

Pingback: Key Lock box Security – not as secure as you might think – update |

Pete

said:By the way, I just found time to try to unlock the Supra lock box on my front door.

I did unlock it in 4 minutes picking the numbers from the list I posted above. 🙂

And definitely there 210 Combinations only and the order of pressing the push-buttons are not important.

The formula is C= 10! / 4!(10-4)!

Cheers

Peter

bugadvisor

said:Thanks Pete, the list you sent certainly looks correct and your formula matches the one I have in my update to this post https://bugadvisor.com/2013/08/09/key-lock-box-security-not-as-secure-as-you-might-think-update. I won’t publish the list of numbers in your previous comment as I don’t want to encourage people to break into houses using this knowledge.

Jere Neal

said:I understand your reasoning for not having the list used for the wrong reason, but it is so easy to produce with a simple bit of programming, that it would probably help more people than it would hurt. Just my opinion… I would assume that most of the people asking are the owner of the lock. The list I have includes 210 4-digit combinations, but if all of the 1- and 2- and 3-digit combinations are included, it jumps to 385 unique possibilities. If you are trying to open your own lock, I suggest eliminating your own and your family’s birth-year or anniversary first, just in case it may save time 🙂

anonymous

said:BTW, I have basic math skills and Excel. It took me less than 30 minutes to come up with all codes using Excel. I start with 1024 rows and 10 columns. For the first column, 512 rows have 1, the rest zero. For the second column, 128 rows have 1, 128 rows have zero. I copy these 256 rows to the bottom. For the third column, 64 rows have 1 and 64 rows with zero and I copy the 128 rows to the bottom. For the forth column, 32 rows have 1 and 32 rows have zero. I copy all 64 rows to the bottom. I do the same reduction in pattern for each column and by column 10 one row has 1 the other row has zero and I copy these two rows to the bottom. Copying the rows is simple as Excel repeats the pattern all the way down so it only takes a few seconds to do for each column. In column 11, I sum the first 10 columns to get the total digits. I insert a row at the top and label the first 10 columns 1, 2, 3, 4, 5, 6, 7, 8, 9, and 0. In columns 13-22 I start at row 2 and insert a formula. For cell N2 its =IF(B2=1,B$1,””), I copy this formula from cell N2 to W1025. For cell M2 the formula is =CONCATENATE(N2,O2,P2,Q2,R2,S2,T2,U2,V2,W2) and I copy this down to row 1025. That is all there is to it and I now have all the combinations. It is so easy to do and requires only the most basic math and intermediate Excel skills.

bugadvisor

said:Yes it’s certainly possible and I already have the list of combinations. But I’m hoping someone with math and Excel skills wouldn’t use the numbers for nefarious purposes. I haven’t published the list in case it is misused – although I did put a poll on the ‘best of 2013’ page asking for votes on whether the numbers should be published.

anonymous

said:One comment, I started with column B, not column A. I copy / paste special valued columns L and M to a new sheet. I then sorted that new sheet by column A and then by column B. The basic math skill was to come up with a manual binary algorithm to come up with 1024 unique numbers as the total combinations was 2 to the power of 10.

I gave you the complete list to document the above method works. As for publishing the list, I think it will mainly be used by people who forgot their code as I have trouble with the idea that someone would spend the time punching in all those codes if the box is in an open area visible to others. I would absolutely not, under any circumstance, place that box where it is not in view of others at all times like the front of a house in a development because there are so few combinations and the list is so easy to produce.

As a side note, one of the links on your site, fun with numbers, already lists all 3, 4, and 5 digit combinations.

Thanks.

bugadvisor

said:Yes I know the numbers are already in the public domain.

anonymous

said:Also goofed explanation, its 512, 256, 128, 64, 32, ….. Not 512, 128, 64 for coping 1’s.

anonymous

said:I had the opportunity to read up on all the posts including the updated posts. The formula in the updated post is correct and is consistent with the 1024 combinations I uploaded yesterday. The formula on the link shows the following which is 10+45+120+210+252+210+120+45+10 which = 1,022 combinations. In addition, you can select no number or all numbers which brings the total to 1,024.

One of the reasons this interested me is because my exterminator company keeps my gate key in this box. As its only a gate key, I am not too concerned. However, I started thinking how great it would be to keep a separate box for a spare house key.

I’ve used this box at various rentals I’ve stayed at and everyone appears to use 4 digit codes. With 210 combinations, there is a 50% chance of unlocking it after trying only 105 of them. Theoretically, 5 digits is the most secure in terms of combinations, but only by a small amount.

I don’t think most people would try to hack 6 digit numbers. Unless one has a list with them, 7 digits would be just too difficult but there are only 120 of those combinations. I think 6 is best if you use this box. The extra two digits would also slow down anyone trying to hack the box with a list of numbers.

anonymous

said:I spent a few hours researching this problem today and found the box I will use. It is the Kiddie KeySafe P500. Amazon sells it although it is quite a bit more expensive. In addition to 1, 2, 3, 4, 5, 6, 7, 8, 9, and 0 it also has A and B. Those two extra buttons make a huge difference. The total combinations on this are 4,096 or 2 to the power of 12. The numbers in the mid range have nearly 1,000 combinations so you definitely do not want to forget it or your will be spending hours keying in all the combinations from a master list trying to open it. Way more secure.

As a side note, Kiddie is very upfront on the available combinations which I appreciate. On the 10 digit boxes for sale on Amazon, it clearly states over 1,000 combinations are available. On the 12 digit box, it clearly states 4,096 possible combinations.

Alan

said:It may be easy to crack the combination, but to a crackhead or the ordinary criminal, it looks like fort Knox. They do not waste time carefully not damaging your property. If they want in, they come in, they throw a brick through a window or sliding glass door, and they are in. They come in, day or night, and increasingly, when you are home. They are desperate. This is a cost of the top 1% possessing 40% of the wealth.

bugadvisor

said:I agree that many would just smash their way in. I don’t agree that they have an excuse just because they need money. Have a read of this explanation of the tax system explained in beer: http://danieljmitchell.wordpress.com/2012/03/18/the-tax-system-explained-in-beer/

Tom

said:I believe Richard is right. 1024 combinations.

Why?

Because as he says, the setting is a 10 digit binary number (each button can be on or off). 2^10 = 1024.

0000000000,

0000000001,

0000000010,

0000000011,

0000000100,

0000000101,

0000000110,

0000000111,

0000001000,

etc .

(Assuming a code can be any length from 0 to 10 digits).

Order makes no difference. For example 0000000111, it makes no difference what order you press those last 3 digits, 0000000111 is still different from 0000000101.

Paula

said:To be honest you all wrong it doesnt matter what order you type the numbers.

bugadvisor

said:That is what the article already says

Clive

said:Thanks for this

I’ve been looking at these & the more questions I ask the sellers, the more they try to dodge the question as to how many combinations there actually are. I knew I could work it out if I put my mind to it but what’s the point if someone else already has. 🙂

I was trying to work out if the rotary locks had more combinations, despite the fact most people know the old rotary 4 digit bike locks are really not that secure so to find out these 10 digit push button locks are almost 10 times easier to break into, is a major shock but with all of the avoidance I’ve been getting on the question, I’m really not that surprised.

I guess more searching is needed to find a more secure key lock.

Thanks for doing the math.

john

said:I wouldnt use supra lock boxes. We moved into our duplex earlier this year and it had a supra box on the front door. The owner didnt not know the combination to it and said to just leave it be, its safe there. Well 8 months later i was tired of looking at it and know theres a key to the door hanging there. Literally 10 minutes is what it took to break open the box and get the key out. Good job supra.

Ed Hotin

said:Can you send me the list? I know my code is only 4 digits but I forgot it. What proof do you need that I’m legit and not trying to hack into something that isn’t mine? Thanks!

bugadvisor

said:Please send me an email at paul@feagan.com with some more details – the best proof is an open door with the lock box next to it – in a photo

Ed Hotin

said:No problem, just sent it to you! Thanks!

Anon Amous

said:I open them in 15 seconds with large Channel Lock pliers. It takes longer to find my pliers than opening the box. As long as the box is mild steel, this works well. If it were something like cast iron or stainless, this would be difficult. The harder ones would need a saw or grinder. With battery powered tools so common, nothing is safe for long unless the components are made stronger than the ones I have seen.

Dude

said:I used this when I locked myself out yesterday, only took 20 minutes by brute forcing all the combinations, thanks!! Saved me breaking a window or something =)

Mike

said:The instructions to this lock says “use five to seven numbers in your combination”

MIchelle

said:I need to use some kind of lockbox on my doorknob occasionally. Given the flaws, what is the ‘best’ one on the market? Is there any decent reasonably priced one on Amazon?

Mark W. Barrett

said:My Dear Late Father passed on a great deal of wisdom to me; some of which I retained.

One comment was:

“Locks are to keep honest people honest”

Sounded weird at the time; but even the most

Sophisticated forms of security are continually

being challenged by dishonest, twisted, sick

Vermin who choose to violate, hurt and steal

from others who oppose this form of behavior;

and who have been taught, or learn the meaning of integrity.

“Lock On”