创建一个随机字符串

Security.php

<?php
/**
 * author     : forecho <caizhenghai@gmail.com>
 * createTime : 2015/6/10 10:27
 * description: 
 */

class Security
{
    /**
     *  创建一个随机字符串
     * @param   string  the type of string
     * @param   int     the number of characters
     * @return  string  the random string
     */
    public static function random($type = 'alnum', $length = 16)
    {
        switch ($type) {
            case 'basic':
                return mt_rand();
                break;

            default:
            case 'alnum':
            case 'numeric':
            case 'nozero':
            case 'alpha':
            case 'distinct':
            case 'hexdec':
                switch ($type) {
                    case 'alpha':
                        $pool = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
                        break;

                    default:
                    case 'alnum':
                        $pool = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
                        break;

                    case 'numeric':
                        $pool = '0123456789';
                        break;

                    case 'nozero':
                        $pool = '123456789';
                        break;

                    case 'distinct':
                        $pool = '2345679ACDEFHJKLMNPRSTUVWXYZ';
                        break;

                    case 'hexdec':
                        $pool = '0123456789abcdef';
                        break;
                }

                $str = '';
                for ($i = 0; $i < $length; $i++) {
                    $str .= substr($pool, mt_rand(0, strlen($pool) - 1), 1);
                }
                return $str;
                break;

            case 'unique':
                return md5(uniqid(mt_rand()));
                break;

            case 'sha1' :
                return sha1(uniqid(mt_rand(), true));
                break;
        }
    }

}