Here is a guide from the GNU website: https://www.gnu.org/licenses/gpl-howto.en.html

Yes. But it’s despite.

I’d consider btrfs if they finally make their raid5/6 implementation stable. I want to work with multiple disks without sacrificing half of my storage.

If I’m not mistaken you can save keys in these chips so that they can not be extracted. You can only use the key to encrypt/decrypt/sign/verify by asking the chip to do these operations with your key.