HSBC CPI's orderHash generator

This script is an orderHash generator.

When making online payment with HSBC, and you want to use CPI, rather than API, then you should have a hash key generator. Instead of troubling yourself to install HSBC supplied, or the ones you Googled, php extensions (Actually, they are not what you expected more often), it is recommended that you use this generator directly.

The following code include a class and a function. To use this code, the php extensions mhash and mcrypt are the prerequirements. It's not difficult to enable them.

Notice: This code is for PHP professionals

Some instructions:

1. There is no order of array elements. That is, array('a', 'b') is identical with array('b', 'a').
2. The hash key length is always 28 digits.

<?php
/**
* This script is used to generate the hash order key
* which is required by HSBC CPI interface.
*/

/**
* Order information encryption class
* @author Shelley Shyan
* @copyright http://phparch.cn
*/
class orderCrypto {
private $_fldif;
private $a;

public function orderCrypto()
{
$s = 'KmJTwzVPwjoxQdWJb1BxbuhBSa2RuM05+/aUdgYoGdFWWf04CKIQTxtxLeKCp+5J';
$s1 = 'y8YhmjsAoMUW9RxfXBSos0A6LwGd+5pXv/MRAKCYFLG';
$s2 = 'BqRkPAG8DFFAdeN5SMAArktCYuUGXi2q88EDoOs3Ykw0k';
$this->a = chr(98).chr(84).chr(120).chr(114).chr(66).chr(87).chr(80).chr(112);

$this->_fldif = $this->initKey($s, $s1, $s2);
$this->_fldif = substr($this->_fldif,0,44);
}

private function rot13(&$abyte0)
{
for($i = 0; $i < strlen($abyte0); $i++)
{
$c = ord($abyte0[$i]);
if($c >= ord('a') && $c <= ord('m') || $c >= ord('A') && $c <= ord('M'))
$abyte0[$i] = chr($c + 13);
else
if($c >= ord('n') && $c <= ord('z') || $c >= ord('N') && $c <= ord('Z'))
$abyte0[$i] = chr($c - 13);
}
}

private function encode($abyte0) {
return base64_encode($abyte0);
}

private function decode($s) {
return base64_decode($s);
}

private function encrypt($abyte0, $abyte1)
{
$td = mcrypt_module_open (MCRYPT_DES, '', MCRYPT_MODE_CBC, '');
$iv = $this->a;
$ks = mcrypt_enc_get_key_size ($td);
$key = substr($abyte1, 0, $ks);

/* Intialize encryption */
mcrypt_generic_init ($td, $key, $iv);
return mcrypt_generic ($td, $abyte0);
}

private function decrypt($abyte0, $abyte1)
{
$td = mcrypt_module_open (MCRYPT_DES, '', MCRYPT_MODE_CBC, '');
$iv = $this->a;
$ks = mcrypt_enc_get_key_size ($td);
$key = substr($abyte1, 0, $ks);

/* Intialize encryption */
mcrypt_generic_init ($td, $key, $iv);
$ret = mdecrypt_generic($td, $abyte0);

while($ret[strlen($ret)-1] == "\4" && strlen($ret) > 0){
$ret=substr($ret, 0, strlen($ret)-1);
}
return $ret;
}

private function encryptEncode($abyte0, $abyte1)
{
return $this->encode($this->encrypt($abyte0, $abyte1));
}

private function decodeDecrypt($s, $abyte0)
{
return $this->decrypt($this->decode($s), $abyte0);
}

private function initKey($s, $s1, $s2)
{
$abyte0 = chr(0);
$abyte1 = $s1;
$abyte2 = $s2;
$byte0 = 4;
$i = $byte0 + 9;
$j = rand(0, 30);
$j = 0;
if($j > $byte0 * $i) $j -= $byte0 * $i;

$k = 0;
for($l = 0; $l < $byte0 * $i; $l++)
{
switch(($j + $l) % $i)
{
case 0: // '\0'
if($k == 2)
{
$abyte0 = $this->encrypt($abyte1, $abyte2);
$k++;
}
break;

case 1: // '\001'
if($k == 1)
{
$abyte2 = $abyte1;
$this->rot13($abyte2);
$k++;
}
break;

case 2: // '\002'
if($k == 0)
{
$i1 = 48 + (ord($abyte1[0]) + 10) % 10;
$abyte1[0] = chr($i1);
$k++;
}
break;

case 3: // '\003'
if($k == 3) $k++;
break;

case 5: // '\005'
case 7: // '\007'
case 10: // '\n'
if($k < 2) $abyte0 = $this->encrypt($abyte1, $abyte2);
break;

case 4: // '\004'
case 6: // '\006'
case 8: // '\b'
case 9: // '\t'
default:
break;
}
}
return $this->decodeDecrypt($s, $abyte0);
}

public function decryptToBinary($s)
{
if ($s == NULL)
return NULL;
else
return $this->decodeDecrypt($s, $this->_fldif);
}

}//End of Class orderCrypto

//echo "iv size=" . mcrypt_get_iv_size('des', 'cbc') . "<br />";
//echo "key size=" . mcrypt_get_key_size('des', 'cbc') . "<br />";