Also I can highly recommend Introduction to Cryptography course by Christof Paar - https://www.youtube.com/channel/UC1usFRN4LCMcfIV7UjHNuQg (and the text book https://link.springer.com/book/10.1007/978-3-642-04101-3 but you may not need it)
About 2-3 years ago, I've watched all the lectures and then a couple of months ago I've watched them again to remember the details. It's joy watching Christof giving cryptography lectures.