BitLocker stores your encryption keys on a Microsoft server [1] and is a closed-source software, therefore by definition it cannot be trusted for encrypting anything important. (It is wrong even if your adversary is not a state, because that way you are getting used to a false sense of security that you don't actually have.)
It's an option to store your keys on their server, but not a requirement. At least not the last time I set up BitLocker. In fact that computer didn't even have the on board Secure Storage thing that it prefers, so I had to make a note of the recovery key on paper.
"Stores keys on someone's server" cannot be trusted, no matter what the copyright status is of the code running on the server.
Code licensing or copyright status isn't a form of security.
The issue isn't just that the remote server's code is impervious to scrutiny. A locally installed program that you can reverse engineer isn't automatically trustworthy because it is open-source, or even copylefted. Someone actually has to reverse engineer the binary and prove that it matches the source code. Many users of free software trust upstream binaries. (Even if they compile their own programs, they trust compiler binaries at some point.)
Actually, original title by Agatha Christie was "Ten Little Niggers" [1]. I didn't read the book, but I really liked the movie [2] (there is eng subs). People in reviews say it's closest and probably best adaptation. IMO, it's excellent.
In France, the original title is still used ("10 petits nègres").
I read the book, but I did not really enjoyed it. But it was a long time ago, I might have been to Young. Or maybe it was the style, which was very different from what I was used to at the time (mostly Ellis Peters)
No. Please don't break the site guidelines by commenting about downvotes. If you feel like a comment has been unfairly downvoted, give it a corrective upvote and move on. That's what others did in this case, and the comment now has a positive score.
How using Gmail could be called secure? According to Snowden docs Google is cooperating with N/S/A. So all your data is collected and stored for future analysis when needed. If you consider this to be "secure" then the whole discussion on security is pointless.
[1] https://theintercept.com/2015/12/28/recently-bought-a-window...