On +2020-08-09 18:17:48 -0400, Mark H Weaver wrote: > > Note that although base32 encodes 5 bits per character, the first > character of a base32-encoded sha256 hash can only be 0 or 1, since > there's only 1 bit remaining to encode after the other 255 bits have > been encoded in the last 51 characters. > UIAM, that's only true for the nix flavor (which is default for guix hash, I think) of base32. Again UIAM, the nix view of a 256-bit sha256sum hash is little-endian, and shifts 5 bits out the bottom, as if with euclidean/ 32, and so winds up with the 1 or 0 last, at the top.
I think all the others base32's shift 5 bits at a time from the big end, and could have the full range 0-31 for the top digit, however translated to glyphs. Which also means the last value on the right is a 1 or 0 in the top bit, valued 16 or 0. Of course, different length digests may produce other remainder end values. BTW, how did nix get such a weird alphabet for 0-31 ? Watermarking themselves? :) -- Regards, Bengt Richter