What is the combination probability?

Caporegime
Joined
24 Oct 2012
Posts
25,063
Location
Godalming
Digilocks are ornamental, on most of them you can simply shine a light at the right angle and see which buttons were pressed due to the marks left by fingers. Add to this the fact that the sequence is irrelevant and they're pointless.
 
Associate
Joined
7 Mar 2015
Posts
1,044
Digilocks are ornamental, on most of them you can simply shine a light at the right angle and see which buttons were pressed due to the marks left by fingers. Add to this the fact that the sequence is irrelevant and they're pointless.

hah , i always wondered how safe those safe's you get at a tourist hotel are.
 
Man of Honour
Joined
29 Mar 2003
Posts
56,812
Location
Stoke on Trent
We have digilocks or the mechanical digilocks on every door in our Trust.
The digilocks only need 4 numbers and the mechanical digilocks require you to press C first and 4 numbers and a letter.
I had a debate on Wednesday with a colleague, I told another colleague the door code was CZ1234 but my colleague argued it was C4231Z.
I turned to the woman and said "use CZ1234" but the other colleague argued so I said go and try it.

Also like Diddums said, I was trying to get into Cardiology but forgot the number, I shined my phone light at the keypad and you could see the 4 most used ones.
 
Caporegime
Joined
26 Aug 2003
Posts
37,506
Location
Leafy Cheshire
We have digilocks or the mechanical digilocks on every door in our Trust.
The digilocks only need 4 numbers and the mechanical digilocks require you to press C first and 4 numbers and a letter.
I had a debate on Wednesday with a colleague, I told another colleague the door code was CZ1234 but my colleague argued it was C4231Z.
I turned to the woman and said "use CZ1234" but the other colleague argued so I said go and try it.

Also like Diddums said, I was trying to get into Cardiology but forgot the number, I shined my phone light at the keypad and you could see the 4 most used ones.

The mechanical ones don’t “need” C pressing, only if someone has pressed an incorrect button beforehand.

Of course you have no way of knowing if someone has already mashed the keypad or not, so pressing C every time will certainly cut out the faffing those times the code doesn’t work, but that doesn’t mean C is needed.
 
Man of Honour
Joined
5 Dec 2003
Posts
20,999
Location
Just to the left of my PC
hah , i always wondered how safe those safe's you get at a tourist hotel are.

They'll protect your stuff from people who know nothing about the subject and haven't read the easily obtained manual for the safe and won't force the safe open mechanically. So they're probably generally somewhat safe.

Just for jollies, here's the lockpicking lawyer showing 3 ways to open a locked hotel safe. Two of which only require reading the easily obtained manual and 1 of which requires minimal skill in lockpicking.


There are worse "safes". He once opened a "safe" with a fork. Just a standard household eating fork. Someone jokingly mentioned a spoon because a fork was too easy, so he did another video showing that - opening the "safe" with a spoon. And opening another "safe" with a plastic child's toy figure. Or soft drink cans. There are a fair few "safes" that are so bad that a person with relevant skills doesn't even need any lockpicking tools.

Although it could be said that hotel "safe" in the video is worse because it can be opened by anyone who has read the easily obtained manual. Without any tools at all. Not even a spoon.
 
Man of Honour
Joined
13 Oct 2006
Posts
91,164
Just for jollies, here's the lockpicking lawyer

After watching a few of his videos it was surprising looking around how many every day lock I encounter could be opened with a simple shim and pretty much no skill :s

Reminds me of college and the doors with 4 pin combos and someone found if you put pressure on at a slight angle any combination would work with a little jiggling.
 
Soldato
Joined
9 Mar 2012
Posts
10,072
Location
West Sussex, England
Surely this is:

1/10 x 1/9 X 1/8 x 1/7 x 1/3

You start with a 1 in 10 chance of getting a correct number regardless of it needing to be the first in a set sequence and so on with a diminishing number of numbers to choose from.

So 10x9x8x7x3 = 15,120 : 1 chance of guessing correctly.
 
Associate
Joined
23 Aug 2005
Posts
1,273
the X is 'execute' pressed at the end of every attempt
the C is cancel and start again
the Y can be included in the 'code'
any code is meaningless, its just an arrangement of ones and zeros.
so the combination is
1234567890Y = each set to 0 or 1
00000000000
<snip> every combination of those inbetween
11111111111
= 11 bits, so 1024?
It's unlikely to are allowed nothing as the code :) so 1023, much less if the code is fixed to 4 digits, that would be:
11 x 10 x 9 x 8 ? = 7920
1 in 11
2 in 10
3 in 9
4 in 8
ok thats wrong
lol stream of conscienesnss safe cracking
the chances of me guessing the first correct one is for a 4 length code
there is a row of 1s set, so eg the code was set like this:
1234567890Y
10010011000 = my 'code' is 1478 and its also 4187 etc
this is the failure of such a lock, I have a 4 in 11 chance of guessing the correct code digit, every time I press a button. nuts.
That's not 40% as its 4 out of 11 so its slightly less than 40% less, erm how does maths work again. need coffee.
so its like 36% * length of code (4 digits vs 5 etc)
 
Soldato
Joined
28 Nov 2003
Posts
11,600
Location
Manchester, UK
If the order of numbers/letters does not matter then the chance of hitting the first one correct is 5/13 as it could be any 4 out of the 10 numbers OR any 1 out of the 3 letters. Need a pen and paper to work it out.
 
Back
Top Bottom