Re: Device with multiple partitions
The difference with TrueCrypt was that the "hidden" partition was actually the same partition as the main one, just read in reverse and with a different key. The theory is that as all the "blank space" in a TrueCrypt volume is randomised, it should be impossible to tell whether such a reverse volume even exists. i.e. it provides at least plausible deniability.
Of course, it was up to the user to ensure that the total space used on both partitions was sufficiently small to ensure that they didn't collide, and that there was enough on the "declared" partition to justify its existence other than as a "cover" - I believe that a few (legal) porn videos that one might wish to hide from SWMBO was the most common content.