How many possible combinations in 9 character? I have a question because i cant solve it myself i dont realy know how to calculate it exactly, i know it's gonna be easy for you in this section..
So i have 2 questions,
I want my computer to generate all possibility of 9 character, with: only uppercase alphabetic, and number
so exemple:
A5S8E5D8E5
How many possibility is possible ? , no lower case, only uppercase and number.
And if its possible to know, how many time it would take to guess all possibility ?
I know it depend of the configuration of my computer but well let's say a 1080 GTX.
Thank for your help guys !
 A: So you have 26 possibilities for upper-case letters and 10 possibilities for digits meaning you have 36 possibilities for each character. In total you obtain that number:
$$
36^9 \simeq 10^{14}
$$
To see how long it would take for a GPU to crack it, we would need to test the hash of a password and compare it to the hash stored in the database. So it depends on the algorithm you use to produce the hash and check in the database. To get an idea, from this website (for MD5 encryption), we get that a GTX 1080 processes $4 \times 10^{10}$ hashes per second. So you get a rough estimate of $2500s$ which is less than an hour.
Note that it blows up if you use all possibilities from your keyboard.You get 10 digits + 26 lowercase + 26 uppercase + 31 special characters which is 93. Then the numbers of possibilities gets to $10^{17}$ and it takes roughly 1 month non-stop to exhaust all possibilities.
A: For each character, you have $26$ letters + $10$ digits = $36$ possible choices.
Therefore, the total number of combinations is $36^9$, which is a really big number.
I'm not sure about computation time though, since I'm not a hardware expert.
A: This problem is called a permutation with repetition. The sequence here involves 26 letters of the English alphabet and 10 numbers from 0 to 9.
This turns out to be a simple calculation. So we can form a sequence of 9 characters by selecting one letter/number out of 36 for each character, which gives us:
$$36 \times 36 \times 36\times 36\times 36\times 36\times 36\times 36\times 36 = 36^9 = 101559956668416 \simeq 10^{14} $$
To estimate the total time required you need to know the execution time of your algorithm needed for testing a sequence of 9 characters, then you multiply by $36^9$ times.
