[hashcash] Re: hashcash-1.15 released

  • From: Jonathan Morton <chromi@xxxxxxxxxxxxxxxxxxxxx>
  • To: hashcash@xxxxxxxxxxxxx
  • Date: Sun, 16 Jan 2005 17:45:31 +0000

There is scope to adapt Jonathan's fastmint code directly to make
compact stamps, just more complicated, so I may make that change in
future.  I believe Jonathan estimated it should be only around 15%
slower if done that way, and I think this slow down would be

Libfastmint should already handle -Z1 stamps as-is, with the ~15% penalty (over -Z0) because some optimisations aren't available.

However, -Z2 stamps would still be about 2x slower than -Z1, because the primary limitation is the need to hash two SHA1 blocks per try instead of one, and I don't plan to support them in libfastmint. The whole point of libfastmint was to gain a minimum 2x improvement over the old OpenSSL-heritage code, and -Z1 basically emulates the original libfastmint behaviour.

Personally, I simply plan to use -Z0. :-) But another good strategy for servers might be to use -Z1 normally, and switch to -Z0 in overload conditions.

To make life easier for users, how about naming them -turbo, -normal, and -compact? I don't think -normal stamps are visually "too big" for most people, so that's another argument against trying to make -compact stamps faster. Especially if it would potentially make -turbo slower.

from:     Jonathan "Chromatix" Morton
mail:     chromi@xxxxxxxxxxxxxxxxxxxxx
website:  http://www.chromatix.uklinux.net/
tagline:  The key to knowledge is not to rely on people to teach you it.

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