Encrypt in VB.NET and Decrypt in PHP and Vice Versa

[FarooqRafiq]

Hi,

My requirement is that a string is encrypted in VB.NET and sent to PHP, PHP decrypts the string (till here the logic is working) and then the PHP should encrtyp (where i am having problems) and send the data to VB.NET application. The proble is in encrypting in PHP side.


PHP Code

<?php
//$syscode=$_REQUEST['syscode'];
//The actual string is "blueberry" which is encrypted in VB.NET and sent to PHP
$syscode = "8yN73RDmMFuXo9ux8QKC6w=="; //This is the encrypted string as received from VB.NET
echo "Original Encrypted String Received from VB.NET: <br>".$syscode;
echo "<br><br>";
Decrypt($syscode);
echo "<br><br>";
Encrypt("blueberry");
 
 
function Decrypt($strToDecrypt){
global $strD;
$key64 = "cPSQAC05GBXzMhRRz7tm8cqg+vHdHyN5";
$iv64 = "jIShBJVBfXo=";
$encryptedString64 = $strToDecrypt;
$keybytes = base64_decode($key64);
$ivbytes = base64_decode($iv64);
 
$encryptedStringbytes = base64_decode($encryptedString64);
 
// use mcrypt library for encryption
$decryptRaw = mcrypt_decrypt(MCRYPT_3DES, $keybytes, $encryptedStringbytes, MCRYPT_MODE_CBC, $ivbytes);
$decryptString=trim($decryptRaw,"\x00..\x1F");
print "Decrypted by PHP:<br>$decryptString<br/>"; //The decrypted string should be "blueberry"
}
 
function Encrypt($strToEncrypt){
$key64 = "cPSQAC05GBXzMhRRz7tm8cqg+vHdHyN5";
$iv64 = "jIShBJVBfXo=";
$keybytes = base64_decode($key64);
$ivbytes = base64_decode($iv64);
 
// use mcrypt library for encryption
$encryptRaw = mcrypt_encrypt(MCRYPT_3DES, $keybytes, $strToEncrypt, MCRYPT_MODE_CBC, $ivbytes);
$encryptString=(base64_encode(trim($encryptRaw)));
 
print "Encrypted in PHP:<br>$encryptString<br/>"; //This where the PHP encrypted result is not matching the VB.NET encryption result.
}
?>
 

VB.NET Code

Imports System
Imports System.Text
Imports System.Security.Cryptography
Imports System.IO
 
Module Crypto
    Public Function Decrypt(ByVal strToDecrypt As String) As String
        Try
 
            'initialize our key
            Dim tripleDESKey As SymmetricAlgorithm = SymmetricAlgorithm.Create("TripleDES")
            tripleDESKey.Key = Convert.FromBase64String("cPSQAC05GBXzMhRRz7tm8cqg+vHdHyN5")
            tripleDESKey.IV = Convert.FromBase64String("jIShBJVBfXo=")
 
            'load our encrypted value into a memory stream
            Dim encryptedValue As String = strToDecrypt
            Dim encryptedStream As MemoryStream = New MemoryStream()
            encryptedStream.Write(Convert.FromBase64String(encryptedValue), 0, Convert.FromBase64String(encryptedValue).Length)
            encryptedStream.Position = 0
 
            'set up a stream to do the decryption
            Dim cs As CryptoStream = New CryptoStream(encryptedStream, tripleDESKey.CreateDecryptor, CryptoStreamMode.Read)
            Dim decryptedStream As MemoryStream = New MemoryStream()
            Dim buf() As Byte = New Byte(2048) {}
            Dim bytesRead As Integer
 
            'keep reading from encrypted stream via the crypto stream
            'and store that in the decrypted stream
            bytesRead = cs.Read(buf, 0, buf.Length)
            While (bytesRead > 0)
                decryptedStream.Write(buf, 0, bytesRead)
                bytesRead = cs.Read(buf, 0, buf.Length)
            End While
 
            'reassemble the decrypted stream into a string    
            Dim decryptedValue As String = Encoding.ASCII.GetString(decryptedStream.ToArray())
 
 
            Return (decryptedValue.ToString())
 
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Function
 
    Public Function Encrypt(ByVal strToEncrypt As String) As String
        Dim sa As SymmetricAlgorithm = SymmetricAlgorithm.Create("TripleDES")
        sa.Key = Convert.FromBase64String("cPSQAC05GBXzMhRRz7tm8cqg+vHdHyN5")
        sa.IV = Convert.FromBase64String("jIShBJVBfXo=")
 
        Dim inputByteArray() As Byte = Encoding.ASCII.GetBytes(strToEncrypt)
        Dim mS As MemoryStream = New MemoryStream()
 
        Dim trans As ICryptoTransform = sa.CreateEncryptor
        Dim buf() As Byte = New Byte(2048) {}
        Dim cs As CryptoStream = New CryptoStream(mS, trans, CryptoStreamMode.Write)
        cs.Write(inputByteArray, 0, inputByteArray.Length)
        cs.FlushFinalBlock()
 
        Return Convert.ToBase64String(mS.ToArray).ToString
    End Function
End Module