although my research about the Demonware authentication/master server is not complete (and I highly doubt to continue due to the lack of interest) I guess I can link here a tool I wrote to "start" to analyze this data: http://aluigi.org/papers/dwcryptonet.zip
it's totally useless for the people but it's a good start for understanding a bit about the protocol and the types of encryptions to expect to find.
quick usage: dump the content of ALL the connections made to port 3074 of the demonware master server in one raw file and then launch the tool specifiying it and the own "secretsauce".
if you don't know the secretsauce just use your nickname and the bracketsless cdkey (it will calculate it, it's just the XORing of these two parameters).
if the game doen'st use a secretsauce (like Enemy Territory Quake Wars demo) just put a zero or ""