Some information, if needed:
OK, my dear ladies and gentlemen, i want to say that NO NEW encryption was implemented in 6.0.5.0 patch. NO NEW packets were added in this patch. It was just a game for children and you're faked
How UO works before this patch: client sends seed (4 bytes, really local IP-address) and then sends packets for login server stage authorization.
How UO works after this patch: client sends seed (same 4 bytes), THEN SENDS 17 NEW BYTES, after this sends packets for login server state authorization. That's all! It's very simple, really? OK, now for these 17 cursed bytes
First byte is random value, usually it's last byte of seed, because first byte of seed is really new byte and our IP begins from second byte.
Next 16 bytes is client version - 00 00 00 06 00 00 00 00 00 00 00 05 00 00 00 00
So, all we need is to expand seed buffer for new clients.