The need for post-quantum cryptography arises from the fact that many popular encryption and signature schemes schemes based on ECC and RSA can be broken using Shor's algorithm for factoring and computing discrete logarithms on a quantum computer. Bibcode : OExpr.. The best solution could be a combination of post-quantum algorithms like lattice-based encryption for the initial communication to securely exchange keys, then using symmetric encryption for the main messages. Bibcode : AdOP Download as PDF Printable version. Each time you visit a website with a secure connection i. Physical Review A.