Creating a 14 character 'random key generator'

Question

I'm trying to use CodeIgniter to write up a small program for school which generates a random 'key' every time I click the 'generate' button. Looking to see if there's a way for me to create a function where I can fill up a 14 character array with a random number or letter and then set the array to a variable which I can call upon to display as my generated key.

Any and all help would be much appreciated as I am new to CodeIgniter.

sorry, i'm also using CSS in my code but realized that it's not part of the problem i'm running into — Alex Kim, Feb 03 '15 at 18:43

SidOfc · Accepted Answer · 2017-06-13T09:17:09.543

A while back I wrote this function in PHP, it does what it does and gives you some flexibility as well through complexity modifiers, I used a default set of 5 different 'levels' of characters and the length is also variable ofcourse.

I'm just going to chuck it in here and 'try' to explain what is going on as well as I can by comments:

function rsg($length = 10, $complexity = 2) {
        //available 'complexity' subsets of characters
        $charSubSets = array(
            'abcdefghijklmnopqrstuvwxyz',
            'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
            '0123456789',
            '!@#$%^&*()_+{}|:">?<[]\\\';,.`~',
            'µñ©æáßðøäåé®þüúíóö'
        );

        // will be filled with subsets from above $charSubsets
        $chars = '';

        //concact each subset until complexity is reached onto the $chars variable
        for ($i = 0; $i < $complexity; $i++)
            $chars .= $charSubSets[$i];

        //create array containing a single char per entry from the combined subset in the $chars variable.
        $chars = str_split($chars);
        //define length of array for mt_rand limit
        $charCount = (count($chars) - 1);
        //create string to return
        $string = '';
        //idk why I used a while but it won't really hurt you when the string is less than 100000 chars long ;)
        $i = 0;
        while ($i < $length) {
            $randomNumber = mt_rand(0, $charCount); //generate number within array index range
            $string .= $chars[$randomNumber]; //get that character out of the array
            $i++; //increment counter
        }

        return $string; //return string created from random characters
    }

This is what I currently use and it has satisfied my needs for quite some time now, if anyone reading over this has improvements I'd love to hear them as well!

i originally had this -- function random($len = 14) { $chars = array( 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' ); shuffle($chars); $num_chars = count($chars) - 1; for($i = 0; $i < $len; $i++) { $token .= $chars[mt_rand(0, $num_chars)]; } return $token; } and it didn't seem to like it — Alex Kim, Feb 03 '15 at 17:05

score 1 · Answer 2 · answered Feb 03 '15 at 02:35

1

$a=array(rand(10000000000000, 99999999999999));

is a quick way to get a 14 digit array.

answered Feb 03 '15 at 02:35

menriquez

239
4
17

3

`mt_rand()` does a better job than `rand()`. – Josiah Keller Feb 03 '15 at 02:45

score 0 · Answer 3 · edited May 23 '17 at 11:59

It depends on how random you want it to be. You could specify all characters you want in a $characters string, then just create a string up to $length, picking a random substring of length 1 from the characters string.

What are the requirements? Do you want it to be as random as possible (This link might be useful) Are multiple occurrences of one character allowed in one random string?

Here's an example though: PHP random string generator

Creating a 14 character 'random key generator'

3 Answers3

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