Isn't that the promise of FileVault on a Mac? Is that not under discussion here because it's not good, or because it's not cross-platform? (In other words, should I not trust FileVault?)
For starters, how would we know? The software in question is closed-source and has spotty docs as best - and more importantly: your trust in a software is something that only you can establish for yourself, irregardless if whatever number of people on the internet claim the product trustworthy.
Appelbaum on FileVault(1) in 2006: http://events.ccc.de/congress/2006/Fahrplan/attachments/1244...