[Boost-bugs] [Boost C++ Libraries] #12022: CRT optimised powm()

Subject: [Boost-bugs] [Boost C++ Libraries] #12022: CRT optimised powm()
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-02-26 10:29:02

#12022: CRT optimised powm()
------------------------------+----------------------------
 Reporter:  psiha             |      Owner:  johnmaddock
     Type:  Feature Requests  |     Status:  new
Milestone:  To Be Determined  |  Component:  multiprecision
  Version:  Boost 1.61.0      |   Severity:  Optimization
 Keywords:                    |
------------------------------+----------------------------
 multiprecision::powm() with unchecked uints is _much_ slower (i.e. I
 actually perceive the time it takes for the function to return on an 4GHz
 i5 in release builds) than say the equivalent libtomcrypt/math operation.
 I'm guessing the major reason for this is the
 https://en.wikipedia.org/wiki/RSA_(cryptosystem)#Using_the_Chinese_remainder_algorithm
 optimisation (or lack thereof in multiprecision).
 So, can you implement a CRT 'enabled' powm overload (I presume this would
 also require a function for factoring a large multiprecision uint into to
 dp, dq, etc. factors)?

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/12022>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.