Attacking a password using brute force?

Question

How do you calculate how long a computer would take to crack a password using brute force? For example, if the password was

Aiediew9r389032iopouuiKJJIe3

How long would it take a computer to find this code by calculating every possible combination? Thanks!

Answer 1

Let's suppose you have n characters in the password string.
Possible characters include 26 lower case, 26 upper case, and 10 digits. That's 62.
So total no. of possibilities = 62^n
In your case n = 28, which means there are
1.5 x 10^50 combinations.

Some programs will crash at about 10^10

Answer 2

This depends on if the computer knows how many characters are in the password and what characters are available. If the password is n characters long and there are x different characters available, the number of possibilities is x^n. You need to multiply this by the amount of time it takes for the computer to check each code, which is a piece of data you'd need to be supplied with.

Your password is 28 characters long and contains letters (both upper and lower case) and numbers. Suppose the password is known only to be at most 30 characters long and to be alphanumeric with case sensitivity. That means that there are 62 possibilities for every character (10 numbers, 26 capital letters, 26 lower-case letters). And since we don't know the actual length, we need to try every combination of 1 character, 2 characters, 3 characters, all the way up to 30 characters. So the computer must test 62 + 63^2 + 62^3 + ... + 62^30 possible passwords.

Answer 3

I guess how "fast" a computer computes will be a big factor however to find the combinations:

It looks like the password can be any letter, CAPS or not, plus any number 0-9. So you have a total of 26+26+10 = 62 options for each digit (plus "blank") if its at the end. So let's just say 63 options for each "digit".

Your password is 28 characters long - let's assume a maximum of 30 characters. So you have 63^30 different combinations or 9.55 * 10^53 different passwords.

Now let's assume you have a computer that can test 1,000,000,000 (one billion) passwords per hour.

In that case, it would take you 9.55*10^44 hours, 3.98*10^43 days, 1.09*10^41 years to test all of the passwords.

So, it would take a very long time!

Hope this helps...

Answer 4

In order to crack a password like that, the computer must go through every possibility till it hits it. Since there are uppercase and lowercase letters and also numbers, there are 62 possibilities for each digit, and there are 28 digits.

62^28 = 1.53803885 × 10^50
Bear in mind the universe is only 10^18 seconds old.
Even a supercomputer sending password after password to another supercomputer 3 inches away at light speed couldn't make a dent in that. And with all the users who choose "password", who would bother trying?

Of course that password will be a devil to memorize.

Answer 5

As an easier example, let's look at A1.

There are 128 characters in ASCII, and the computer will most likely go in hexidecimal order, but I will do the decimal equivalents for number of operations.

Now assuming it is stored in an array:
First the computer will do the first digit, A.
That will take 65 operations.
Next it will do the second digit, 1.
That will take 49 operations.
Total: 114 operations.

If it is not stored in an array, but rather a string, it will take much longer (see David's answer).

If you want to know how long yours would take, click the source and add up all the decimal equivalents.

Answer 6

Just contact the email provider and ask how to recover or reset a lost password. Most of these email services have a "Forgot Password" indicator you can use when you log on. I suggest you write down passwords and security questions and the answers in a notebook for each account or computer you have. Keep the notebook in a safe place for future reference.