security – What is the optimal way to protect my data from my VPS provider?

What is the optimal way to protect my data (db and source code) from my hosting provider?

Would using an encrypted volume, such as truecrypt, suffice? However – for my program to access data on the encrypted volume, it needs to be unlocked and mounted – does this make it pointless.

I’ve heard of homomorphic encryption, but:
A) I have no idea where to start, and
B) I’d need to decrypt the data before presenting it to the rightful origin/user