PHP Encryption and VB.net Decryption

Question

I am trying to complete a simple task. Fix the value in PHP and decrypt it in your VB.net application. I believe I will use tripleDES or Rijdael 128 or 256

Although it should be simple. Can someone point me in the right direction?

thanks

Answer 1

We have some ciphers working between C # on .NET and PHP. I am not familiar with VB.net. I guess it uses the same cryptographic library System.Security.Cryptography.

On the PHP side, we switched from mcrypt to OpenSSL because some modes and paddings are not supported by mcrypt.

(DES, AES ..), (CBC, ECB ..), (PKCS1, PKCS5), .

AES-128 PHP mcrypt,

    $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
    $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
    $blockSize = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128);
    $data = $this->paddingAlgorithm->padData($data, $blockSize);
    return $iv . mcrypt_encrypt($this->MCRYPT_DES, $keyBytes, $data, MCRYPT_MODE_CBC, $iv);

, PKCS7, mcrypt , . IV ( ) . , .

# ,

    // create the underlying symmetric algorithm with the given name
    algorithm = (SymmetricAlgorithm)CryptoConfig.CreateFromName("RIJNDAEL");
    // set cipher mode
    algorithm.Mode = CipherMode.CBC;
    // set padding mode
    algorithm.Padding = PaddingMode.PKCS7;

Answer 2

. php vb.net, , . #.

########################################
# BEGIN PHP CODE
########################################


<?php

ini_set('display_errors', 1);
error_reporting(E_ALL);

// I blantantly stole, tweaked and happily used this code from: 
// Lord of Ports http://www.experts-exchange.com/M_1736399.html


$ky = 'lkirwf897+22#bbtrm8814z5qq=498j5'; // 32 * 8 = 256 bit key
$iv = '741952hheeyy66#cs!9hjv887mxx7@8y'; // 32 * 8 = 256 bit iv

$text = "Here is my data to encrypt!!!";

$from_vb = "QBlgcQ2+v3wd8RLjhtu07ZBd8aQWjPMfTc/73TPzlyA=";   // enter value from vb.net app here to test

$etext = encryptRJ256($ky, $iv, $text);
$dtext = decryptRJ256($ky, $iv, $etext);
$vtext = decryptRJ256($ky, $iv, $from_vb);

echo "<HR>orignal string: $text";
echo "<HR>encrypted in php: $etext";
echo "<HR>decrypted in php: $dtext";
echo "<HR>encrypted in vb: $from_vb";
echo "<HR>from vb decrypted in php: $vtext"; 
echo "<HR>If you like it say thanks! richard dot varno at gmail dot com";


exit;



function decryptRJ256($key,$iv,$string_to_decrypt)
{

    $string_to_decrypt = base64_decode($string_to_decrypt);

    $rtn = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, $string_to_decrypt, MCRYPT_MODE_CBC, $iv);

    $rtn = rtrim($rtn, "\0\4");

    return($rtn);

}


function encryptRJ256($key,$iv,$string_to_encrypt)
{

    $rtn = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, $string_to_encrypt, MCRYPT_MODE_CBC, $iv);

    $rtn = base64_encode($rtn);

    return($rtn);

}    

?>

########################################
# END PHP CODE
########################################



########################################
# BEGIN VB.NET CODE (console app)
########################################

Imports System
Imports System.Text
Imports System.Security.Cryptography
Imports System.IO

Module Module1

    ' I blantantly stole, tweaked and happily used this code from: 
    ' Lord of Ports http://www.experts-exchange.com/M_1736399.html

    Sub Main()

        'Shared 256 bit Key and IV here
        Dim sKy As String = "lkirwf897+22#bbtrm8814z5qq=498j5"  '32 chr shared ascii string (32 * 8 = 256 bit)
        Dim sIV As String = "741952hheeyy66#cs!9hjv887mxx7@8y"  '32 chr shared ascii string (32 * 8 = 256 bit)

        Dim sTextVal As String = "Here is my data to encrypt!!!"

        Dim eText As String
        Dim dText As String

        eText = EncryptRJ256(sKy, sIV, sTextVal)
        dText = DecryptRJ256(sKy, sIV, eText)

        Console.WriteLine("key: " & sKy)
        Console.WriteLine()
        Console.WriteLine(" iv: " & sIV)
        Console.WriteLine("txt: " & sTextVal)
        Console.WriteLine("encrypted: " & eText)
        Console.WriteLine("decrypted: " & dText)
        Console.WriteLine("If you like it say thanks! richard dot varno at gmail dot com")
        Console.WriteLine("press any key to exit")
        Console.ReadKey(True)

    End Sub

    Public Function DecryptRJ256(ByVal prm_key As String, ByVal prm_iv As String, ByVal prm_text_to_decrypt As String)

        Dim sEncryptedString As String = prm_text_to_decrypt

        Dim myRijndael As New RijndaelManaged
        myRijndael.Padding = PaddingMode.Zeros
        myRijndael.Mode = CipherMode.CBC
        myRijndael.KeySize = 256
        myRijndael.BlockSize = 256

        Dim key() As Byte
        Dim IV() As Byte

        key = System.Text.Encoding.ASCII.GetBytes(prm_key)
        IV = System.Text.Encoding.ASCII.GetBytes(prm_iv)

        Dim decryptor As ICryptoTransform = myRijndael.CreateDecryptor(key, IV)

        Dim sEncrypted As Byte() = Convert.FromBase64String(sEncryptedString)

        Dim fromEncrypt() As Byte = New Byte(sEncrypted.Length) {}

        Dim msDecrypt As New MemoryStream(sEncrypted)
        Dim csDecrypt As New CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read)

        csDecrypt.Read(fromEncrypt, 0, fromEncrypt.Length)

        Return (System.Text.Encoding.ASCII.GetString(fromEncrypt))

    End Function


    Public Function EncryptRJ256(ByVal prm_key As String, ByVal prm_iv As String, ByVal prm_text_to_encrypt As String)

        Dim sToEncrypt As String = prm_text_to_encrypt

        Dim myRijndael As New RijndaelManaged
        myRijndael.Padding = PaddingMode.Zeros
        myRijndael.Mode = CipherMode.CBC
        myRijndael.KeySize = 256
        myRijndael.BlockSize = 256

        Dim encrypted() As Byte
        Dim toEncrypt() As Byte
        Dim key() As Byte
        Dim IV() As Byte

        key = System.Text.Encoding.ASCII.GetBytes(prm_key)
        IV = System.Text.Encoding.ASCII.GetBytes(prm_iv)

        Dim encryptor As ICryptoTransform = myRijndael.CreateEncryptor(key, IV)

        Dim msEncrypt As New MemoryStream()
        Dim csEncrypt As New CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write)

        toEncrypt = System.Text.Encoding.ASCII.GetBytes(sToEncrypt)

        csEncrypt.Write(toEncrypt, 0, toEncrypt.Length)
        csEncrypt.FlushFinalBlock()

        encrypted = msEncrypt.ToArray()

        Return (Convert.ToBase64String(encrypted))

    End Function

End Module

########################################
# END VB.NET CODE
########################################

Answer 3

PHP mcrypt, .

Answer 4

Disclaimer: I have never used Crytography classes in .NET.

To do Rijndael decryption in .NET, you are probably looking for the System.Security.Cryptography.RijndaelManaged class .

There are also examples on this page of how to use it, although you might also need an instance of RSACryptoServiceProvider ... I'm not sure.