I attended the Introduction to Cryptography by Martin Mareš in the winter semester 2021/2022. I don't remember who said it but I quite agree with the statement that cryptography constists of the most beautiful parts of algebra bundled together. These notes should cover all what was done in lectures (and sometimes a bit more). I still wouldn't use them as the primary learning source because they are sometimes too brief. Combining it with watching lectures and searching for more in-depth explanations on the web is better.