I can intuitively understand the math behind RSA and DH (though EC is a bit hand-wavey with the "dot" operation [1]). But I have yet to grasp latticed-based stuff [2] or 'learning with errors' [3] yet.

[1] https://arstechnica.com/information-technology/2013/10/a-rel...

[2] https://www.youtube.com/watch?v=QDdOoYdb748

[3] https://www.youtube.com/watch?v=K026C5YaB3A