Get a random alphanumeric string.

randomkeys.php

	/**
	 * @param $prefix
	 * @param $suffix
	 * @param $size
	 *
	 * @return string
	 */
	private function randomKey($prefix, $suffix, $size)
	{
		$key 	= "";
		$chars	= "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
		for ($i = 0; $i < $size; $i++)
		{
			$key .= $chars[rand(0, strlen($chars) - 1)];
		}
		return $prefix . $key . $suffix;
	}