[IrishEyes]

Ok, I feel really out of my element in this forum, because I hardly ever post here, but here goes.
This one is for Turtle, C1ay, Buffy, or any of you other number-crunchers that can help my sleep-deprived brain on this...

background: trying to understand basic computer security, using a 'password' as an example.

How many different charactrer combinations are there for a 4 character password? And what is the equation for that?

There are 26 lower case letters, 26 uppper case letters, 10 numbers, 32 special characters, for a total of 94 possible characters, right? At least that's what it looks like on my keyboard...

[Fishteacher73]

Indepth explanation on permutations..
http://en.wikipedia.org/wiki/Permutation

[C1ay]

Originally Posted by IrishEyes

Ok, I feel really out of my element in this forum, because I hardly ever post here, but here goes.
This one is for Turtle, C1ay, Buffy, or any of you other number-crunchers that can help my sleep-deprived brain on this...

background: trying to understand basic computer security, using a 'password' as an example.

How many different charactrer combinations are there for a 4 character password? And what is the equation for that?

There are 26 lower case letters, 26 uppper case letters, 10 numbers, 32 special characters, for a total of 94 possible characters, right? At least that's what it looks like on my keyboard...

Well, many programs don't allow certain characters like / or \. For 94 characters though, there is 94*94*94*94 4 place combinations since each of the 4places can be any of the 94 possible characters. That's 78,074,896 possibilities.

[Buffy]

Heh, heh, you're probably looking for a simple answer, eh?

Okay, lets specify the problem further to simplify: lets say you are going to ONLY allow 4 character passwords, neither shall they be less than 4 nor more than 4, 4 shall be the number and not greater and not less ("oh stop channeling the Python chaps, B!")

so you correctly counted 94 possible characters ("neither shall it be a chinese keyboard..."), although some of those special characters are disallowed, but lets say its 94.

SO

You can have 94 for the first character and for each of those characters
You can have 94 for the second character and for each of those characters
You can have 94 for the third character and for each of those characters
You can have 94 for the fourth character

and so you have:

94*94*94*94 = 78,074,896 combinations.
Lots huh!

It gets more complicated if you allow more or less characters, but the idea is the same...

Combinatorically,
Buffy

[C1ay]

Originally Posted by Fishteacher73

Indepth explanation on permutations..
http://en.wikipedia.org/wiki/Permutation

Generally permutations refers to sets where each elements is only allowed to be used once as with lotteries. With Irish's question members of the set are not limited to one use, i.e. aaaa is valid since you can reuse characters.

[Fishteacher73]

Oops....

[IrishEyes]

Thanks guys. That's what I thought, which is kinda scary since I am not a number-brain person.
Nemo is writing some type of program that goes along with this, but came up with some HUGE number combinations the first time he ran it. I didn't think the numbers should be so big, and neither did he, so we're trying to figure it out.
You have, as usual, been a great help.
And thanks for K.I.S.S., Buffy... That's just the way i like my math...very understandable!

(Oh ,my, new smileys as well! )