The hardness assumptions, lattices and protocols that keep communication and computation secure.
Public-key encryption, signatures and homomorphic encryption whose security rests on Learning With Errors, the basis of the NIST post-quantum standards ML-KEM and ML-DSA.
The fastest known classical algorithm for factoring large integers, implemented in CADO-NFS; public RSA challenge factorisations measure its real cost and set RSA key-size policy.