[mattiask]

From what I gathered Truecrypt provides plausible deniability through hidden volumes that appear to be random data. AFAIK it doesn't allow you to have a partition that when you decrypt with a certain password transforms to alternate content. So if the feds know you have something encrypted you might be in trouble.

[dedward]

well, it lets you have a fully functional alternate system (both systems are encrypted) that will show up if the correct password is used, with no direct forensic way to prove it exists at all, by design. There indirect ways, outlined intheir faqs quite well, that could beused to suggest you have multiple instqnces, like multiple windows updates for thesame updates from th same system, that kinda thing..... but with enough diligence you could pull it off. there are also some write restrictions iirc - may enim wrong but i think if you write to the alternate system you cansquash data inadvertently from the primary as thesecondary can have no knowledge of thereal system in any way, makingn this unavoidable.

pulling this off would require a level of diligence most people justdonthave, andthere are easierways to hide your data.