I was just reading Little Brother (the Cory Doctorow book) and I thought about how awesome it would be if, on startup, a computer asked for a password. Depending on the password, it could open different partitions.
Say I was captured by someone and I had my computer – they could demand the password, and I’d give the innocuous one that unlocks the non-sensitive partition. Is this possible?
TrueCrypt supports adding a single “hidden volume” to an encrypted container or partition. It can include a hidden operating system as well. (The secret data should be located in the hidden volume.)
If your system uses LUKS, you could modify the initramfs to conditionally unlock multiple partitions, but this is less secure as anyone can extract the unlock script.