[tor-bugs] #9663 [Tor]: Table-based basepoint multiply optimizations for ntor handshake

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#9663: Table-based basepoint multiply optimizations for ntor handshake
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     Reporter:  nickm    |      Owner:
         Type:           |     Status:  needs_revision
  enhancement            |  Milestone:  Tor: 0.2.7.x-final
     Priority:  normal   |    Version:
    Component:  Tor      |   Keywords:  tor-relay, performance, ntor,
   Resolution:           |  026-triaged-0, 027-triaged-1-in
Actual Points:           |  Parent ID:  #9662
       Points:           |
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Comment (by yawning):

 Replying to [comment:19 nickm]:
 > Makes sense.

 I don't think the ed25519 stuff is particularly critical path (yet), so
 the numbers that really matter are the curved25519 figures.  I guess we
 can call for someone to test the various options on those sorts of targets
 when we integrate the code.

 > > Will we ever consider removing the ref10 code/fallback stuff?  I don't
 think it particularly makes a difference to how I'm going to do this, but
 I think the portable versions of the donna code is well tested at this
 point.
 >
 > We can consider removing it, sure.  I think I'd like to leave it in for
 a while as a fallback though.

 Makes sense.  Ironically, by pulling in all of ed25519-donna, our codebase
 grew a 2nd copy of ref10, since it's included as part of the "fuzz vs the
 ref implementation" stuff that's in the source tree.

 I'm thinking something along the lines of:
  * 0.2.7.x-alpha: Cross check on startup, crosscheck every N operations.
  * 0.2.7.x-stable: Cross check on startup.
  * 0.2.8.x-alpha: Yank the ref10 code, assume that people run "make check"
 and that our unit tests catch pathological compiler failures.

 With progression along each phase being dependent on nothing totally
 horrific cropping up.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/9663#comment:20>
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