I'm currently making my own server aiming to be one where you can basicly just walk around but working with the latest version of the client.
My issue is with the decryption of the data sent by the client, I set K for the encryption which I created from the AUTH_LOGON_PROOF package.
Encrypting packets seems to work fine as the SMSG_AUTH_RESPONSE I sent gets accepted by the client and it sends a new request but when I try to decrypt it I just get garbage.
I use the RC4 engine/WoWCrypt from hearthstone.