How so? Currently known symmetric crypto algorithms are secure against attacks by quantum computers. More than that, hash functions, which are building primitiv

How so? Currently known symmetric crypto algorithms are secure against attacks by quantum computers. More than that, hash functions, which are building primitives of password hashing functions, are used in "post-quantum crypto", e.g. for signatures (https://en.wikipedia.org/wiki/Post-quantum_cryptography#Hash-based_Cryptography https://en.wikipedia.org/wiki/Post-quantum_cryptography#Hash..., http://sphincs.cr.yp.to/ http://sphincs.cr.yp.to/). (Although more research should be done on memory-hard functions.)