[Cryptography] mathematical constants

[Peter Gutmann]

Pierre Abbat <phma at bezitopo.org> writes:

>Is there a place where we can collect mathematical constants for use as
>nothing-up-my-sleeve numbers?

The problem is that with any kind of famous irrational number you're mostly
relying on people believing that the hex string you're using somehow
corresponds to an encoding of Noodleheinz's Constant or whatever [0].  I'd go
with either some well-known piece of text ("Friends, Romans, countrymen...")
if low entropy is OK or the same thing run through HKDF if you need high
entropy, that's pretty easy for anyone to verify.

Peter.

[0] Has anyone ever verified things like the SHA-2 constants?  How are the
    fractional parts of square/cube roots encoded to get the hex values?