GenRandID

PHP Class for generating unique non chronological ids from a number list

This code is part of a larger project where we needed user ids that would be simple to remeber but hard to predict.

Example

require_once('class.GenRandID.php');

$ab=new GenRandID();
$i=1;

while ($i <= 500) {
    echo "$i ::"; 
    $enc=$ab->encode($i);
    echo "$enc ::";
    echo $ab->decode($enc)." <br />";
    $i++;
}

Full Code

<?php
class GenRandID {
    // All the vowels, some consonants and some numbers have been removed
    public $TR_ENC = '56789dfghjklmnpqrstvwz';
 
    function __construct() {
        $this->BASE=strlen($this->TR_ENC);
        $this->TR_DEC=substr('0123456789abcdefghijklmnopqrstuvwxyz',0,$this->BASE);
    }
    public function encode($userID) {
        $rand=rand(10,99);
        $newID=$userID.$rand;
        $base=base_convert($newID, 10, $this->BASE); 
        $transl=strtr($base, $this->TR_DEC, $this->TR_ENC);
        return($transl);
    }
    public function decode($userID) {
        $transl=strtr($userID, $this->TR_ENC, $this->TR_DEC);
        $base=base_convert($transl, $this->BASE, 10); 
        $userID=substr($base, 0, -2);
        return($userID);
    }
}
?>