This gets into the weird history of these "Right Answers" documents, which I deeply regret ever help make into a thing. Colin Percival wrote the first one, in the long-long-ago, and he's the author of Tarsnap, a (very good) encrypted backup service. I wrote the next "Right Answers" document as a response to Percival's, because I felt his "Right Answers" were very idiosyncratic and wanted to put conservative normie answers on the record. Because I like Colin (and Tarsnap), my "Right Answers" had a Tarsnap recommendation, and so have subsequent ones.
I think it's past time for this "Right Answers" cryptography meme to die, though. Filippo's PQC recommendations are good. Let's hope this is the last such document we ever need.
> I think it's past time for this "Right Answers" cryptography meme to die, though.
Politely disagree. I read Colin's when it came out and it was as useful in 2009 as Filippo's is today. If you only pay attention to the cryptography community every few years when you need it for something, then usually a whole lot has happened in the interval. It is incredibly useful to get the perspective of someone paying attention to give you a breakdown of "where we're at today".
A great example is the other conversation about SHA-256. Colin's recommendation was "hey, better plan to migrate from this in the future." The thing that's happened between then and now is, well, SHA-256 is actually still 'ok' when used in current constructions. That's useful to know in 2026.
If I get busy building stuff, it'll be nice to have a check-in again in a few years (or earlier if something significant happens first).
That works if you just follow the "Right Answers" documents in Filippo's chronology here, but there are more besides that. The bigger issue is just that this particular set of issues --- forget the answers, just the questions themselves --- is itself idiosyncratic. A very particular set of cryptography engineer stands to get any value out of a "Right Answers" document like this; everybody else is sort of misled into thinking they understand more than they do (or that the field has been adequately summed up, or whatever).
None of this is to say Filippo's is bad.