At first i thought it was the padding since mcrypt uses zero padding but i changed the php to use PKCS7 and get the same exact results
Can anyone help? I think it has something to do with the padding in the php
Test output from .Net:
Key: d88f92e4fa27f6d45b49446c7fc76976
Text: Testing123
Encrypted: /DMkj7BL9Eu2LMxKhdGT+A==
Encrypted after base64 decode: ?3$??K?K?,?J???
Decrypted: Testing123
Test output from PHP:
Key: d88f92e4fa27f6d45b49446c7fc76976
Text: Testing123
Encrypted: K+ke5FNI5T6F6B/XvDF494+S8538Ze83cFz6v1FE89U=
Encrypted after base64 decode: +éäSHå>…è×¼1x÷’óüeï7p\ú¿QDóÕ
Decrypted: Testing123����������������������
PHP:
class rijndael{
var $mcrypt_cipher = MCRYPT_RIJNDAEL_256;
var $mcrypt_mode = MCRYPT_MODE_CBC;
function decrypt($pass, $encrypted)
{
$encrypted = base64_decode($encrypted);
$key = $this->getkey($pass);
$iv = $this->getiv($pass);
$decrypted = mcrypt_decrypt($this->mcrypt_cipher, $key, $encrypted, $this->mcrypt_mode, $iv);
$block = mcrypt_get_block_size($this->mcrypt_cipher, $this->mcrypt_mode);
$pad = ord($decrypted[($len = strlen($decrypted)) - 1]);
return substr($decrypted, 0, strlen($decrypted) - $pad);
}
function encrypt($pass, $decrypted)
{
$key = $this->getkey($pass);
$iv = $this->getiv($pass);
$block = mcrypt_get_block_size($this->mcrypt_cipher, $this->mcrypt_mode);
$pad = $block - (strlen($str) % $block);
$str .= str_repeat(chr($pad), $pad);
$encrypted = mcrypt_encrypt($this->mcrypt_cipher, $key, $decrypted, $this->mcrypt_mode, $iv);
return base64_encode($encrypted);
}
function getkey($passphrase)
{
$L1 = base64_encode(hash("sha256", $passphrase, true));
$L2 = $passphrase.$L1;
return hash("sha256", $L2, true);
}
function getiv($passphrase)
{
$L1 = base64_encode(md5($passphrase));
$L2 = $passphrase.$L1;
return md5($L2);
}
}
VB .Net:
Public Class RijnDael
Public Shared Function Decrypt(ByVal sData As String, ByVal sKey As String)
Dim bytData() As Byte = Encoding.UTF8.GetBytes(sData)
Return Decrypt(bytData, sKey)
End Function
Public Shared Function Decrypt(ByVal bytData As Byte(), ByVal strPass As String) As Byte()
Dim bytResult As Byte()
Using oRM As New System.Security.Cryptography.RijndaelManaged
oRM.KeySize = 256
oRM.Key = GeKey(strPass)
oRM.IV = GetIV(strPass)
oRM.Mode = CipherMode.CBC
oRM.Padding = PaddingMode.PKCS7
Using oMS As New MemoryStream(bytData)
Using oCS As New Cryptography.CryptoStream(oMS, oRM.CreateDecryptor, Security.Cryptography.CryptoStreamMode.Read)
Dim TempDecryptArr As Byte()
ReDim TempDecryptArr(bytData.Length)
Dim decryptedByteCount As Integer
decryptedByteCount = oCS.Read(TempDecryptArr, 0, bytData.Length)
'
ReDim bytResult(decryptedByteCount)
Array.Copy(TempDecryptArr, bytResult, decryptedByteCount)
'
oCS.Close()
End Using
oMS.Close()
End Using
End Using
Return bytResult
End Function
Public Shared Function Encrypt(ByVal sData As String, ByVal sKey As String)
Dim bytData() As Byte = Encoding.UTF8.GetBytes(sData)
Return Encrypt(bytData, sKey)
End Function
Public Shared Function Encrypt(ByVal bytData As Byte(), ByVal strPass As String) As Byte()
Dim bytResult As Byte()
Using oRM As New Cryptography.RijndaelManaged
oRM.KeySize = 256
oRM.Key = GeKey(strPass)
oRM.IV = GetIV(strPass)
oRM.Mode = CipherMode.CBC
oRM.Padding = PaddingMode.PKCS7
Using oMS As New MemoryStream
Using oCS As New Cryptography.CryptoStream(oMS, oRM.CreateEncryptor, Cryptography.CryptoStreamMode.Write)
oCS.Write(bytData, 0, bytData.Length)
oCS.FlushFinalBlock()
bytResult = oMS.ToArray()
oCS.Close()
End Using
oMS.Close()
End Using
End Using
Return bytResult
End Function
Private Shared Function GeKey(ByVal strPass As String) As Byte()
Dim bytResult As Byte()
'Generate a byte array of required length as the encryption key.
'A SHA256 hash of the passphrase has just the required length. It is used twice in a manner of self-salting.
Using oSHA256 As New Cryptography.SHA256Managed
Dim L1 As String = System.Convert.ToBase64String(oSHA256.ComputeHash(Encoding.UTF8.GetBytes(strPass)))
Dim L2 As String = strPass & L1
bytResult = oSHA256.ComputeHash(System.Text.Encoding.UTF8.GetBytes(L2))
oSHA256.Clear()
End Using
Return bytResult
End Function
Private Shared Function GetIV(ByVal strPass As String) As Byte()
Dim bytResult As Byte()
'Generate a byte array of required length as the iv.
'A MD5 hash of the passphrase has just the required length. It is used twice in a manner of self-salting.
Using oMD5 As New Cryptography.MD5CryptoServiceProvider
Dim L1 As String = System.Convert.ToBase64String(oMD5.ComputeHash(Encoding.UTF8.GetBytes(strPass)))
Dim L2 As String = strPass & L1
bytResult = oMD5.ComputeHash(System.Text.Encoding.UTF8.GetBytes(L2))
oMD5.Clear()
End Using
Return bytResult
End Function
End Class
The problems in your two pieces of code are:
Use Rijndael-128 with a key and block size of 16 bytes / 128 bit in both the .NET and the PHP code. For Rijndael-256, your code generates an IV with the wrong length. And I don't know how to use AES-256 in PHP (key length of 32 bytes / 256 bits, block size of 16 bytes / 128 bit).
Use of MD5: In the PHP code, add a second parameter true to the md5() function (in two places) so the result is binary data and not a hexadecimal string.
In the encrypt() function in your PHP code, replace the variable $str with $decrypted (in two places). $str is never assigned a value and never used, so the padding has no effect.
If you fix these problems, then both programs will return the result:
Encrypted: /DMkj7BL9Eu2LMxKhdGT+A==
I haven't tried to decrypt it.