first of all, sorry for my english I'm french... nobody's perfect

I'm loocking over internet for some days to encrypt transmission 2.33.
I've found some answers but they are for versions less than 2.33.
I've been in preferences >> confidentiality
then in encryption mode >> I've got autorized encryption, prefered encryption, required encryption (wich one do I have to choose ?)
I've selected PEX and DHT to find more peers.
is that right ?
hox do I know if all exchanges are encrypted ? how can I bee anonymous with Transmission ?
Thanks for your help.
Transmission 2.33 on Xubuntu 11.10.