C# working on kms 1.23 version(year 2003 version) and AES encryption problem..

Hi.

Sorry for my short english language in advance.

I'm just currently working on kms 1.23 version.
(or just kms version 223)

It's very old version and I think It was developed in year 2003~2004.

Here is my progress.



I currently working with two kinds of different server.
One for the kms 1.2.6 (based on java) and one for the kms 1.55(based on c#)

and I'm trying to modify the kms 1.55 server source to get work with kms 1.23 client.

I don't know about packet structures and header's function..
so I'm referring to 1.2.6 java source code to know about packet structures and header's function.

The problem is I can't get any further from login screen.
When I intentionally input wrong password and then click submit button, The client crashes.

I programmed to send packets like this when the server get wrong password:


0x01 -> header(login check result)
0x04 0x00 0x00 0x00 -> login result(Int) (0x04 for wrong password)
0x00 0x00 -> (short) (I don't know why but my 1.2.6 server sends additional two bytes.)

when I send this packet, Client just crashes like this.




as far as I know, If i send any bytes from server to client, The client just crashes.
and I think It's not just the problem of my packets, It's problem of AES encryption/decryption.

The AES encryption does not work properly for 1.23 client.

(It does work when I send "Gethello" packet. but in the source code, "Gethello" packet doesn't need encryption and is sent through raw packet.)

What should I do now?
The AES encryption Key is different from client to client depending on version?

Sorry for my bad english,
But I'm just newbie and I need any advice of professionals like you.