Are there any Cryptography Algorithms that involve Lots of Number Theory?
The Falcon digital signature algorithm is as &quot;meaty&quot; as one can be.

It has an NTRU-like key generation procedure and public key lattice structure;

its security is based on conjectured difficulty of lattice reduction in classical and quantum computers;

its efficiency is based on number-theoretic transformation and fast discrete normal distribution sampling;

its compactness is based on entropy coding.


Some more to be listed.