Speaking of Bitlocker, I'm reminded of TrueCrypt.
My home desktop is configured for dual-booting, and I was looking into using TrueCrypt for drive encryption, since it works for multiple operating systems. TrueCrypt wasn't available in the repositories for Fedora Linux, and the immediate reason was a group of concerns about TrueCrypt's licensing terms. The biggest problem with the license terms is that the TrueCrypt developers explicitly retain the right to sue users for copyright violations -- making it unclear what rights users have to use TrueCrypt.
From what I can make out, where things really get weird is that no one is sure who the developers are, and the FSF, et. al., haven't been able to reach them to discuss changes in the licensing terms.
TrueCrypt is open source, and supposedly experts have checked the source code thoroughly, so it seems unlikely that there's a back door embedded in that code. But the weirdness of the license, and the mystery about the identity of the developers, strikes me as possibly significant, given what we're hearing now about the NSA's efforts to poison standards and push software developers to add back doors.