On: Quantum is unimportant to post-quantum

[charlieyu1]

By 1990s they were pretty rubbish. DES could be cracked by home PCs for a couple of days.

[thombat → charlieyu1]

That's not quite correct. The first (public) brute-forcing of DES was done in 1997 by the DESCHALL project distributing the search across tens of thousands of volunteer's computers for weeks [1]. The EFF then spent $250,000 to build a dedicated DES cracker ("Deep Crack") which required an average of four days per key found [2]

[1] https://en.m.wikipedia.org/wiki/DESCHALL_Project

[2] https://en.m.wikipedia.org/wiki/EFF_DES_cracker

[kadoban → charlieyu1]

DES itself is an example of the NSA being ahead of the field. The designed the S-box to be resistant against attacks nobody knew about yet.

Like the sibling comment points out, you're overstating the weakness of DES as well.