[tor-bugs] #9667 [Tor]: Consider batch-exponentiation tricks to improve ntor performance

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#9667: Consider batch-exponentiation tricks to improve ntor performance
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     Reporter:  nickm   |      Owner:
         Type:  defect  |     Status:  new
     Priority:  normal  |  Milestone:  Tor: 0.2.5.x-final
    Component:  Tor     |    Version:
   Resolution:          |   Keywords:  tor-relay performance ntor
Actual Points:          |  Parent ID:  #9662
       Points:          |
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Comment (by rransom):

 Curve25519 implementations use the ‘Montgomery ladder’ (a fixed
 differential addition chain which is easy to implement in a side-channel-
 resistant manner), not the ‘square-and-multiply method’.  The square-and-
 multiply method would be unacceptably slow.

 Brauer's algorithm (on Edwards-form group elements) ''might'' be worth
 considering.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/9667#comment:1>
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