The tutorial style article about encrypted control systems and encrypting dynamic controllers is now published:
Comparison of encrypted control approaches and tutorial on dynamic systems using Learning With Errors-based homomorphic encryption
Junsoo Kim, Dongwoo Kim, Yongsoo Song, Hyungbo Shim, Henrik Sandberg, and Karl H. Johansson
published in Annual Reviews in Control
Here’s the link: https://www.sciencedirect.com/science/article/pii/S1367578822001031