Re: FoRKBusters up again

Robert Harley (
Mon, 24 Nov 1997 16:26:33 +0100 (MET)

>Ok FoRKBusters were up to 460th place. [...]
>p.s. is Rob involved in this? Rob???

Uhhh, nope. RC5 sucks on 64-bit machines because Rivest purposely
designed it for Intel chips with lots of 32-bit rotates:

y := x <<< s

becomes something like:

s := s & 31
y := (x << s) & 0xffffffff | (x >> 32-s)

i.e. six instructions! So my Alpha only gets 620K iters/sec. But
don't worry, Wayne and I are plenty busy with another challenge,
finding a discrete log on an elliptic curve... we've got a little over
4 GHz worth of Alphas attacking it and have done 980 billion
iterations so far.

Later, Borkfusters!
-- R.