encryption - How to share an encrypted storage on Windows, Mac OS X and Linux in a secure way

I got a 2 TB drive that I have to use with both Windows 8.1 / Windows 10 and Yosemite to OS X / OS X El Capitan and maybe even on Linux.

I need to encrypt the volume. Or rather, I want to create two partitions: a 1.7 TB encrypted and unencrypted the remaining space.

Now I use Windows BitLocker to 512bit. On Mac and Linux nothing, obviously.

What do you recommend?

I saw TrueCrypt (and I read about all the confusion created after May 2014), of VeraCrypt, of GNUPG, Disklocker to read BitLocker on Unix.

But I feel lost and without a good idea.

And if I use TrueCrypt 7.1a waiting for new solutions such as precautions to prevent memory dumps and other potential crack?

And then how should I use TrueCrypt to format the drive? In GPT? MBR? Journaled? FAT?