There is no need to update symmetric key sizes as part of the post-quantum transition, due to the details of how Grover's algorithm scales. Most authorities agree.
I think the article basically says current symmetric key encryption, even 128-bit, but especially 256-bit, is safe from quantum computers, maybe forever. It’s the asymmetric encryption that’s going to be easily broken, and this is what Google says needs to be addressed by 2029.
I think the article basically says current symmetric key encryption, even 128-bit, but especially 256-bit, is safe from quantum computers, maybe forever. It’s the asymmetric encryption that’s going to be easily broken, and this is what Google says needs to be addressed by 2029.