Php Generate A 8 Character Unique Key
I was working on a project recently that required unique API keys to be generated for clients connecting to the server. For various reasons, I settled on the style of license key you commonly see for software packages. You know, the kind you always had to read off the back of a CD case and type in when installing the application. Like H8OV7-HNTB5-JLLOH-W8FG2
.
PHP/MySQL - Best way to create unique random string? How to generate unique id in. Records and check to database table and provides Unique key with store. Php artisan make:migration createuserstable The new migration will be placed in your database/migrations directory. Each migration file name contains a timestamp, which allows Laravel to determine the order of the migrations.
It’s fairly easy to write such a function. The basic idea is to loop around four times—once for each segment—and have a nested loop that runs five times, picking a random character each time. Here’s what I came up with:
The $tokens
/microsoft-2010-key-generator-download.html. string contains the characters that are valid in the key, so the loop can pick from it. The $segment_chars
and $num_segments
variables are the number of characters in a segment and the number of segments in the key, respectively. $key_string
is an empty string that the loop will add the characters into.
The first for loop runs four times, assuming the desired result is four segments in the key. The inner loop picks a character out of $tokens
at random each time it goes around. (PHP strings are also arrays, with the each character having its own numerical offset.) The characters are tacked onto the $segment
string.
Then the segment is joined with the $key_string
, and a dash character is applied if the loop isn’t on the final segment yet. End result: something like H8OV7-HNTB5-JLLOH-W8FG2
.
Now how can you make sure the key is unique when it’s generated?
Php Generate A 8 Character Unique Key Switch
You generate a new key string with the function, check to see if it exists in your database, and lather/rinse/repeat until that is no longer the case. Usually you won’t have collisions too often, so it will only need to run once. I’m too lazy to figure out the probability, but considering there are 52,521,875 possible combinations for one 5-character segment…you’re probably not going to run into performance issues anytime soon. And if you do, just add another segment onto your key strings.
![Character Character](https://3.bp.blogspot.com/-RKNWhjVVGTg/XpKcwnjTLTI/AAAAAAANFrA/tozG3BkQff8wHdL3eD-IIsUIh9TFaeghwCNcBGAsYHQ/s640/s-l1600-4.jpg)
Php Generate A 8 Character Unique Key Code
Here's an example to show the distribution of random numbers as an image. Credit to Hayley Watson at the mt_rand page for the original comparison between rand and mt_rand.
rand is red, mt_rand is green and openssl_random_pseudo_bytes is blue.
NOTE: This is only a basic representation of the distribution of the data. Has nothing to do with the strength of the algorithms or their reliability.
<?php
header('Content-type: image/png');
$sizex=800;
$sizey=800;
$img = imagecreatetruecolor(3 * $sizex,$sizey);
$r = imagecolorallocate($img,255, 0, 0);
$g = imagecolorallocate($img,0, 255, 0);
$b = imagecolorallocate($img,0, 0, 255);
imagefilledrectangle($img, 0, 0, 3 * $sizex, $sizey, imagecolorallocate($img, 255, 255, 255));
$p = 0;
for($i=0; $i < 100000; $i++) {
$np = rand(0,$sizex);
imagesetpixel($img, $p, $np, $r);
$p = $np;
}
$p = 0;
for($i=0; $i < 100000; $i++) {
$np = mt_rand(0,$sizex);
imagesetpixel($img, $p + $sizex, $np, $g);
$p = $np;
}
$p = 0;
for($i=0; $i < 100000; $i++) {
$np = floor($sizex*(hexdec(bin2hex(openssl_random_pseudo_bytes(4)))/0xffffffff));
imagesetpixel($img, $p + (2*$sizex), $np, $b);
$p = $np;
}
imagepng($img);
imagedestroy($img);
?>