Google 价格加密 DoubleClick 算法之 PHP 版本

class DoubleClick
{

    private $encryptionKey = 'encryptionKey';
    private $integrityKey = 'integrityKey';

    function str2bytes($str)
    {
        $len = strlen($str);
        $bytes = array();
        for ($i = 0; $i < $len; $i++) {
            $byte = ord($str[$i]);
            $bytes[] =  $byte;
        }
        return $bytes;
    }

    function bytes2str($bytes)
    {
        $str = '';
        foreach ($bytes as $ch) {
            $str .= chr($ch);
        }
        return $str;
    }

    function int2bytes($val)
    {
        $ret = [];
        for ($i = 0; $i < 8; $i++) {
            $ret[$i] = ($val >> 8 * (7 - $i) & 0xff);
        }
        return $ret;
    }

    function bytes2int($bytes)
    {
        $val = 0;
        for ($i = 0; $i < 7; $i++) {
            $val = $bytes[$i] & 0xff;
            $val <<= 8;
        }

        return $bytes[7] & 0xff;
    }

    function safeXORBytes($a, $b)
    {
        $ret = [];
        for ($i = 0; $i < 8; $i++) {
            $ret[$i] = $a[$i] ^ $b[$i];
        }

        return $ret;
    }

    function urlsafe_b64encode($string)
    {
        $data = base64_encode($string);
        $data = str_replace(array('+', '/', '='), array('-', '_', ''), $data);
        return $data;
    }

    function urlsafe_b64decode($string)
    {
        $data = str_replace(array('-', '_'), array('+', '/'), $string);
        $mod4 = strlen($data) % 4;
        if ($mod4) {
            $data .= substr('====', $mod4);
        }
        return base64_decode($data);
    }

    public function Encrypt($price)
    {
        $microtime = microtime();
        $iv = substr($microtime, 11) . substr($microtime, 2, 6);
        $pad = substr(hash_hmac('sha1', $iv, $this->encryptionKey, true), 0, 8);
        $encPrice = $this->safeXORBytes($this->str2bytes($pad), $this->int2bytes($price));
        $sig = substr(hash_hmac('sha1', $this->bytes2str($this->int2bytes($price)) . $iv, $this->integrityKey, true), 0, 4);

        return $this->urlsafe_b64encode($iv . $this->bytes2str($encPrice) . $sig);
    }

    public function Decriypt($encPriceStr)
    {
        $dprice = $this->urlsafe_b64decode($encPriceStr);
        $iv = substr($dprice, 0, 16);
        $p = substr($dprice, 16, 8);
        $sig = substr($dprice, 24);
        $pricePad = hash_hmac('sha1', $iv, $this->encryptionKey, true);
        $price = $this->safeXORBytes($this->str2bytes($p), $this->str2bytes($pricePad));
        $confSig = substr(hash_hmac('sha1', $this->bytes2str($price) . $iv, $this->integrityKey, true), 0, 4);
        if ($confSig != $sig) {
            return "Decriypt Fail";
        }

        return $this->bytes2int($price);
    }
}

$util = new DoubleClick();

$price = 150;
$encPriceStr = $util->Encrypt($price);
echo $encPriceStr . PHP_EOL;

$decPrice = $util->Decriypt($encPriceStr);
echo $decPrice;

本程序未做严格校验，只是将 golang 写法改成 php 写法，仅供参考