disk encryption for remote server

Hi everyone,

Is there any way to use disk encryption without having physical access to the device?

A few potential ideas:
- is there a way to enter the encryption passphrase via ssh?
- is there a way to create a non encrypted partition on the same hard drive, where the keydisk would be stored, and automatically used? (For various reasons, an external usb key is not feasible). And yes, I realize this would weaken the security significantly, but I'd still like to know if it's feasible?

My guess is that it's not possible, but I wanted to ask to make sure.

Cheers,
Jake