Nah, if the computer is left on I could use a cold boot attack to dump the memory and find the encryption key in there somewhere. If you really want to secure d

Nah, if the computer is left on I could use a cold boot attack to dump the memory and find the encryption key in there somewhere. If you really want to secure devices against physical intrusion you'll need to do a bunch of TPM, anti-intrusion, and smartcard work.