You don't need quantum cryptography to defend against attacks that employ quantum computers. There was an interesting talk on classical encryption algorithms t

You don't need quantum cryptography to defend against attacks that employ quantum computers. There was an interesting talk on classical encryption algorithms that resist quantum attacks by djb and Tanja Lange at 32c3 last year, see [1,2,3]. TL;DR: - Shor's algorithm kills factorization-based algorithms like RSA, DSA and including elliptic-curves-based DSA, - Grover's algorithm allows faster (O(sqrt(N) instead of O(n)) brute-force searches, which means for the same level of security, one needs to double AES key size, - there exist classical encryption algorithms that have so far resisted quantum-based attacks, e.g. hash-based signatures, Goppa code-based asymmetric crypto, [1] https://www.youtube.com/watch?v=6XeBvdm8vao https://www.youtube.com/watch?v=6XeBvdm8vao [2] https://media.ccc.de/v/32c3-7210-pqchacks#video https://media.ccc.de/v/32c3-7210-pqchacks#video (in German) [3] https://www.reddit.com/r/privacy/comments/3yppbz/post_quantum_cryptography_at_32c3/ https://www.reddit.com/r/privacy/comments/3yppbz/post_quantu... EDIT: formatting