Comment 54 for bug 1773457

This doesn't look like it'll ever be done. Based on past experience, I don't think that Canonical takes encryption seriously.

So, I've thrown in the towel. Since buying a new computer, I haven't used dual-boot. Instead, I installed Ubuntu using its full-disk LUKS encryption. I run Windows in a VM (VirtualBox) inside Ubuntu, so that LUKS also protects it.

It's a good solution provided that your hardware is powerful enough. If your hardware isn't up to it, you don't have much choice.