The page you link gives a surface-level description on the area and common techniques. Any remotely detailed explanations on specific topics demand mathematical foundations to be established, which is the approach most respectable cryptography _books_ adopt.

If you allow me to substitute “ring” with “field,” the phrase immediately appears in technique-specific pages (see elliptic curve cryptography: https://en.m.wikipedia.org/wiki/Elliptic-curve_cryptography)

Undergraduate/graduate cryptography courses don’t teach from Wikipedia articles for a reason. It would be a disservice to those learning cryptography to discount the pivotal role of mathematics in the field.