\ticky\crypt\drivergeetest

<?php

namespace ticky\crypt\driver;

use ticky\crypt\contract;

class geetest extends contract {

    private $token;

    public function __construct($config) {

        $this->token = $config['token'];
    }

    // 加密
    public function encrypt($str) {
        $cipher = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_ECB, '');
        $iv = $this->createIv($cipher);
        if (mcrypt_generic_init($cipher, $this->pad2Length($this->token, 16), $iv) != -1) {

            // PHP pads with NULL bytes if $content is not a multiple of the block size..
            $cipherText = mcrypt_generic($cipher, $this->pad2Length($str, 16));

            mcrypt_generic_deinit($cipher);

            mcrypt_module_close($cipher);

            return bin2hex($cipherText);
        }
    }

    public function decrypt($str) {
        $padkey = $this->pad2Length($this->token, 16);
        $td = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_ECB, '');
        $iv = $this->createIv($td);
        if (mcrypt_generic_init($td, $padkey, $iv) != -1) {
            $p_t = mdecrypt_generic($td, $this->hexToStr($str));
            mcrypt_generic_deinit($td);
            mcrypt_module_close($td);
            return $this->trimEnd($p_t);
        }
    }

    // IV自动生成
    private function createIv($td) {
        $ivSize = mcrypt_enc_get_iv_size($td);
        $iv = mcrypt_create_iv($ivSize, MCRYPT_RAND);
        return $iv;
    }

    // 将$text补足$padlen倍数的长度
    private function pad2Length($text, $padlen) {
        $len = strlen($text) % $padlen;
        $res = $text;
        $span = $padlen - $len;
        for ($i = 0; $i < $span; $i++) {
            $res .= chr($span);
        }
        return $res;
    }

    // 将解密后多余的长度去掉(因为在加密的时候 补充长度满足block_size的长度)
    private function trimEnd($text) {
        $len = strlen($text);
        $c = $text[$len - 1];
        if (ord($c) < $len) {
            for ($i = $len - ord($c); $i < $len; $i++) {
                if ($text[$i] != $c) {
                    return $text;
                }
            }
            return substr($text, 0, $len - ord($c));
        }
        return $text;
    }

    //16进制的转为2进制字符串
    private function hexToStr($hex) {
        $bin = "";
        for ($i = 0; $i < strlen($hex) - 1; $i += 2) {
            $bin .= chr(hexdec($hex[$i] . $hex[$i + 1]));
        }
        return $bin;
    }

}