KO Packet Encryption

I am looking to write 1298 KO files from scratch (since we have official files to pull packet opcodes from). But I don't understand the algorithm and how packets are handled before they are sent to the client. I know the packet is build, then sent to be encrypted, and then the header and tail is slapped onto it before its sent. Has anyone been able to write up encrypt/decrypt routines for 1298? I don't want to base my source off public 1098 source. I want to write my server files from scratch. But in order to do that, I need encrypt/decrypt functions for gameserver packets. bıtbıt