Another thing - the linear algebra presented in the article is all at high school or early-university level: systems of linear equations, matrices, row reductio

Another thing - the linear algebra presented in the article is all at high school or early-university level: systems of linear equations, matrices, row reduction, unique solutions, solution space. It might be heavy in terms of quantity, but I would not consider it to be terribly advanced math. I think the only part that most students have not seen is the finite field arithmetic, because that knowledge is pretty specialized for people who actually design math for computers to execute.