Try restarting your browser. It will probably make your encryption options reappear.
The issue has been discussed in another topic (see below), but it’s a bit hidden there, so I wanted to make it more visible by giving it a topic of its own.
As a reminder for other readers, he XSRF error and interactive GUI oddities like missing options in select boxes are very often related.
This is why it’s generally not a good idea to try and continue using the GUI after an XSRF Token error without first refreshing the page or restarting the browser.