Use whichever you like :-)
// Generates Alphanumeric Output
function generateRandomID() {
// http://mohnish.in
$required_length = 11;
$limit_one = rand();
$limit_two = rand();
$randomID = substr(uniqid(sha1(crypt(md5(rand(min($limit_one, $limit_two), max($limit_one, $limit_two)))))), 0, $required_length);
return $randomID;
}
// Generates only alphabetic output
function anotherRandomIDGenerator() {
// Copyright: http://snippets.dzone.com/posts/show/3123
$len = 8;
$base='ABCDEFGHKLMNOPQRSTWXYZabcdefghjkmnpqrstwxyz';
$max=strlen($base)-1;
$activatecode='';
mt_srand((double)microtime()*1000000);
while (strlen($activatecode)<$len+1)
$activatecode.=$base{mt_rand(0,$max)};
return $activatecode;
}