Tutorials: cryptography, vector mathematics, recurrence relations?

Question

Mathematics

Cryptography: preferably a noob level, that is, it should start with the basics of modular arithmetic, and go further from it into deeper topics. Each chapter should have exercises for working out tasks and tasks for full assimilation. How tasks and topics should be arranged at best:

This chela has exercises at the end of each topic. After reading each topic, you need to solve problems, to consolidate the material read, the tasks should be easy, maybe a little medium. The length of the topic is from 3 - 10 pages
in the worst case:
in terms of designing the table of contents for topics and tasks for them - how lucky, the main thing is that it would be read in one breath.

As for vector mathematics, I have doubts. Since there are hardly any where topics do not begin with university formulas. However, if anyone knows a textbook on vector mathematics of a high school of a specialized in-depth level, then this one may suit me.

Recurrent relations are generally part of a textbook of discrete mathematics, so there is little chance that there is such a textbook. But in any case, either the textbook itself or how specific the topic is, it should be chewed up in great detail. That is: from a complex recursive formula to very simple things, it should go so that it would be clear what follows from where, plus exercises.

Answer 1

https://t.me/physics_lib

Answer 2

Cryptography for noobs: A+B+1=1