If I’m reading this right, the oft-repeated nightmare that Quantum computers would render crypto ineffective was, possibly a little overstated?
I’m not sure this was ever really a question.
It was always clear that Shor’s algorithm only applied to very specific problems. Unfortunately it turned out these were the exact problems that were used in pretty much all mainstream public key cryptography. But there always were alternatives.
One likely quantum safe cryptosystem is McEliece, which was developed in the 70s. It is not very practical due to very large keys, so it’s likely not gonna be the one that your future browser will use.
Wikipedia has a good summary. As someone with very, very limited understanding of the mathematics of cryptography, I take the tldr; to be: current symmetric encryption and hash algorithms are probably fine, but will have to double their key size; current public-key algorithms are broken, but there are replacements waiting in the wings.
In 2018, DBJ gave a great talk summarising everything that had been happening in this space up until then. Does anyone know of a similar round-up produced sometime in the last year? It seems post-quantum excitement peaked around 2017. I’m a bit surprised given how serious the issue is.