PHP 手机号中间4位加密

    /**
     * 中间加密 字符串截取法
     */
    public static function encryptTel($tel) {
        $new_tel = substr($tel, 0, 3).\'****\'.substr($tel, 7);
        return $new_tel;
    }

    /**
     * 中间加密 替换字符串的子串
     */
    public static function encryptTel($tel) {
        $new_tel = substr_replace($tel, \'****\', 3, 4);
        return $new_tel;
    }

    /**
     * 中间加密 用正则
     */
    public static function encryptTel($tel) {
        $new_tel = preg_replace(\'/(\d{3})\d{4}(\d{4})/\', \'$1****$2\', $tel);
        return $new_tel;
    }

很实用。