May I ask of some assistance (DllCall Problem)

[SOChaos]

Alrighty, so here I go. Basically, for the past week, I've had problems with this code... I've been trying to write a DLLCall function that is relevant to decrypting a packet from Maplestory. (Part of trying to create a Private server Autoit Based). I've come up with this so far:

Func MapleDecrypt($Data, $Key)
    Dim $PacketLength = StringLen($Data)
    $Dll = DllOpen("MapleCrypto.dll")
    $InBuff = DllStructCreate("byte[" & $PacketLength & "];")
    DllStructSetData($InBuff, 1, $Data)
    $OutBuff = DllStructCreate("byte[" & $PacketLength & "];") 
    DllStructSetData($OutBuff, 1, $Data)
    $IVStructure = DllStructCreate("byte[" & $Key & "];")
    DllStructSetData($IVStructure, 1, $Key)
    DLLCall($Dll, "none", "Decrypt", "str", $Key, _
                                     "ptr", DllStructGetPtr($InBuff), _
                                     "ptr", DllStructGetPtr($OutBuff), _
                                     "int", $PacketLength)
    $Output = DllStructGetData($OutBuff, 1)
    Return $Output
EndFunc

Now, Data would be the Packet incoming from the client, and key would be the SentIV (Which in this case is randomly generated at the beginning of my code..)

But when it runs through the DLLcall, the output is the same as the packet I was trying to decrypt, meaning it's not decrypting at all.. Just outputting the same packet.

Here's how it's called in C#

[DllImport("MapleCrypto.dll")]
        public static extern _ERRCODE Decrypt(byte[] IV, byte[] InputBuffer, byte[] OutputBuffer, int Length);

And if you need the DLL itself, I attached it... I had to rar it due to it's size.

But if anyone can help me figure this out, I'm guessing I'm just missing something in the DLLCall, I guess I'm just thinking about it too hard...

Thankyou in advance.

[Richard Robertson]

In the C# code, the first parameter is listed as a byte array, but in your AutoIt code you used a string. That might be part of the problem, but it's possible that it's not.

[SOChaos]

Yeah I noticed that after I posted it, but there was still nothing changed. I'm wondering what I possibly did wrong. I mean, I know it's my code, but it's driving me nuts.

[Richard Robertson]

A suggestion, try not setting outbuff. Declare it but leave it empty. See if that works.

[SmOke_N]

If it's converted to wide char within the DLL you also may want to do StringLen * 2

[Richard Robertson]

Oh, and I also just noticed, you are using a return type of "none" in the script but the C# returns _ERRCODE which is probably where the code is failing. Find out what _ERRCODE is.

[SmOke_N]

Take Roberts suggestion above, I'm not familiar with C# near as much as he is.

Might try this approach:

Func _MapleDecrypt($s_data, $s_key)
    Local $i_packetlen = StringLen($s_data)
    Local $i_keylen = StringLen($s_key)
    
    Local $t_iv = DllStructCreate("byte[" & $i_keylen + 2 & "]")
    DllStructSetData($t_iv, 1, $s_key)
    
    Local $t_inbuffer = DllStructCreate("byte[" & $i_packetlen & "]")
    DllStructSetData($t_inbuffer, 1, $s_data)
    
    Local $t_outbuffer = DllStructCreate("byte[" & $i_packetlen & "]")
    
    DllCall("MapleCrypto.dll", "int", "Decrypt", _
            "ptr", DllStructGetPtr($t_iv), _
            "ptr", DllStructGetPtr($t_inbuffer), _
            "ptr", DllStructGetPtr($t_outbuffer), _
            "int", $i_packetlen)
    
    Return DllStructGetData($t_outbuffer, 1)
EndFunc

[SOChaos]

Yeah, I'm testing your script right now, it's deffenetly teaching alot about DllCalling. I'm not that great at it. But anyways, you wanted to know what _ERRCODE is, here's the whole DLL Wrapper in C# Form below:

expandcollapse popup

namespace MapleCryptoAPI
{
    public enum _ERRCODE
    {
        ERR_NOERR   = 00,
        ERR_INIT    = 10,
        ERR_NOTINIT = 20,
        ERR_IV    = 30,
        ERR_INPUT   = 40,
        ERR_MEM  = 50,
        ERR_LEN  = 60,
    }

    public enum _CHECK
    {
        True = 1,
        False = 0,
    }

    public class MapleCrypto
    {     
        [DllImport("MapleCrypto.dll")]
        public static extern _ERRCODE Initialize();

        [DllImport("MapleCrypto.dll")]
        public static extern _ERRCODE Finalize();

        [DllImport("MapleCrypto.dll")]
        public static extern _ERRCODE Encrypt(byte[] IV, byte[] InputBuffer, byte[] OutputBuffer, int Length);

        [DllImport("MapleCrypto.dll")]
        public static extern _ERRCODE Decrypt(byte[] IV, byte[] InputBuffer, byte[] OutputBuffer, int Length);

        [DllImport("MapleCrypto.dll")]
        public static extern _ERRCODE EncryptWithHeaderToClient(int Version, byte[] IV, byte[] InputBuffer, byte[] OutputBuffer, int Length);

        [DllImport("MapleCrypto.dll")]
        public static extern _ERRCODE EncryptWithHeaderToServer(int Version, byte[] IV, byte[] InputBuffer, byte[] OutputBuffer, int Length);

        [DllImport("MapleCrypto.dll")]
        public static extern _CHECK HeaderCheckFromClient(int Version, byte[] IV, byte[] Header, int Datalength);

        [DllImport("MapleCrypto.dll")]
        public static extern _CHECK HeaderCheckFromServer(int Version, byte[] IV, byte[] Header, int Datalength);

        [DllImport("MapleCrypto.dll")]
        public static extern _ERRCODE GenerateIV(byte[] IV);

        [DllImport("MapleCrypto.dll")]
        public static extern int GetPacketLengthFromHeader(byte[] Header);
    }
}

Looks like it's just error codes, but Anyways.

I tested your's, Smoke. Seems as if it's just returning nothing but 0x000000000000000000000000. I will continue to work with it. Deffenetly a better code than mine so yeah Lol.

Edited September 21, 2008 by SOChaos

[SmOke_N]

It will be sending back byte data more than likely, so you'll need to do something like:

Return BinaryToString(DllStructGetData($t_outbuffer, 1))

If it's only returning Nulls though, there's either an error with the data your sending, or the way we are sending it.

[Richard Robertson]

Smoke, it's Richard, please.

Can I see an example where the function is being called in C# too? That would allow me to translate it better.

[ProgAndy]

You don't need an example, just make a difference between byte and char, also, the DLL needs initialisation:

CODE

$MapleDLL = DllOpen("MapleCrypto.dll")

; Init DLL

$ret = DllCall($MapleDLL,"long","Initialize")

MsgBox(0, '0=Success', $ret[0])

$CryptKey = StringToBinary("Key001") ; The Key must be in Binary Format

$StringToEncrypt = "The string in packet"

$BinaryData = StringToBinary($StringToEncrypt) ; The Func needs Binary Data

$Crypted = _MapleEncrypt($MapleDLL,$CryptKey,$BinaryData)

MsgBox(0, 'EnCrypted Data', "Data in Binary Format: " & @CRLF & $Crypted & @CRLF& _

@CRLF & "Data as String: "& @CRLF&BinaryToString($Crypted))

$DeCrypted = _MapleDecrypt($MapleDLL,$CryptKey,$Crypted)

MsgBox(0, 'DeCrypted Data', "Data in Binary Format: " & @CRLF & $DeCrypted & @CRLF& _

@CRLF & "Data as String: "& @CRLF&BinaryToString($DeCrypted))

;UnInit DLl

$ret = DllCall($MapleDLL,"long","Finalize")

MsgBox(0, '0=Success', $ret[0])

; $hDll : Handle to MapleCrypt.Dll from DllOpen

; Key and Data as Binary e.g. from BinaryToString

; Returns Encrypted Data as Binary

Func _MapleEncrypt($hDLL, $bKey, $bData)

Local $i_packetlen = BinaryLen($bData)

Local $i_keylen = BinaryLen($bKey)

Local $t_iv = DllStructCreate("byte[" & $i_keylen & "]")

DllStructSetData($t_iv, 1, $bKey)

Local $t_inbuffer = DllStructCreate("byte[" & $i_packetlen & "]")

DllStructSetData($t_inbuffer, 1, $bData)

Local $t_outbuffer = DllStructCreate("byte[" & $i_packetlen & "]")

DllCall($hDLL, "int", "Encrypt", _

"ptr", DllStructGetPtr($t_iv), _

"ptr", DllStructGetPtr($t_inbuffer), _

"ptr", DllStructGetPtr($t_outbuffer), _

"int", $i_packetlen)

Return DllStructGetData($t_outbuffer, 1)

EndFunc

; $hDll : Handle to MapleCrypt.Dll from DllOpen

; Key and Data as Binary e.g. from BinaryToString

; ( Data should normally be Binary when you get it ...)

; Returns Decrypted Data as Binary

Func _MapleDecrypt($hDLL, $bKey, $bData)

Local $i_packetlen = BinaryLen($bData)

Local $i_keylen = BinaryLen($bKey)

Local $t_iv = DllStructCreate("byte[" & $i_keylen & "]")

DllStructSetData($t_iv, 1, $bKey)

Local $t_inbuffer = DllStructCreate("byte[" & $i_packetlen & "]")

DllStructSetData($t_inbuffer, 1, $bData)

Local $t_outbuffer = DllStructCreate("byte[" & $i_packetlen & "]")

DllCall($hDLL, "int", "Decrypt", _

"ptr", DllStructGetPtr($t_iv), _

"ptr", DllStructGetPtr($t_inbuffer), _

"ptr", DllStructGetPtr($t_outbuffer), _

"int", $i_packetlen)

Return DllStructGetData($t_outbuffer, 1)

EndFunc

[SOChaos]

Ah, I see. This makes much more since, I really appreciate it. Thankyou everyone for helping.

[TehWhale]

Nice .dll, but why does this have to have #RequireAdmin to work?