September 14th, 2025
Helpful topic to teach yourself lattice-based crypto: abstract algebra
Lattice-based crypto may work with numbers, but not just any numbers. Thinking in terms of abstract algebra empowers you to set specific rules that allow you to work with certain numbers.
I'll be honest: when talking about lattice-based crypto, I don't know who my audience is. But I do have aspirations that someone with just a high school background can pick up this topic, even if it only means that they'll be able to implement in a rote fashion, rather than having a more nuanced discussion about it. But for people who are actually interested in pursuing certain topics in mathematics, or theoretical cryptography, I'm hoping these articles act as a gateway for them.
There are so many topics to dive into in order to actually have a finer understanding of how things work, but for my first article to my blog about this topic to teach absolute beginners, I'm going to point to a brilliant series that introduces abstract algebra.
At the highest level, lattice-based cryptography builds on the idea of a grid of points (a lattice). We choose a secret point, and then hide it by adding a small, controlled amount of “noise.” But unlike the lattices you might picture from geometry class, these aren’t built from real numbers on graph paper. Instead, the points live in a polynomial ring space, where arithmetic is done with addition, subtraction, and multiplication (but not ordinary division). The rules look familiar, but they play out in a different, more abstract setting.
Unlike university lecture recordings, these series of videos feel a lot more approachable. The tone almost feels like it is welcoming to those who don't even have any experience beyond basic algebra.
Definitely check them out: https://www.youtube.com/playlist?list=PLi01XoE8jYoi3SgnnGorR_XOW3IcK-TP6