Re: Defeating Draconian laws
This is an older one, but there are others:
https://hal.inria.fr/hal-01056376/document
also this has some brief summary:
http://www.forensicswiki.org/wiki/TrueCrypt#Hidden_volumes
The general idea is pattern matching and looking for anomalies in the storage. One way of reducing this apparently is to make sure you use the hidden partition as much as the normal partition as it creates more noise.
Unfortunately the guy who I worked with who could it explain it much better left for a much better paid job!