>Will post-quantum crypto require new hardware? No. We just need to switch from existing public-key cryptographic algorithms to quantum-resistant public-key cr

>Will post-quantum crypto require new hardware? No. We just need to switch from existing public-key cryptographic algorithms to quantum-resistant public-key cryptographic algorithms. There are already a variety of such algorithms developed (see https://en.wikipedia.org/wiki/Post-quantum_cryptography https://en.wikipedia.org/wiki/Post-quantum_cryptography). All that remains is to study them further and agree on a standard. Symmetric ciphers such as AES are already quantum-resistant for 256-bit keys. (Grover's algorithm is the best known quantum attack for such algorithms. Cracking an N-bit key classically is approximately as hard as cracking an (N/2)-bit key on a quantum computer with Grover's algorithm.)