[tor-bugs] #10031 [Obfsproxy]: Use fast modular exponentiation for UniformDH

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#10031: Use fast modular exponentiation for UniformDH
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 Reporter:  phw               |          Owner:  asn
     Type:  enhancement       |         Status:  new
 Priority:  normal            |      Milestone:
Component:  Obfsproxy         |        Version:
 Keywords:  obfs3, uniformdh  |  Actual Points:
Parent ID:                    |         Points:
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 obfs3 currently uses Python's built-in `pow()` for modular exponentiation.
 The computation can be made less expensive by using GMPY.  Apart from
 making UniformDH computationally less expensive, it creates less of a
 timing signature.  That's relevant for ScrambleSuit as its two
 authentication methods should be indistinguishable.

 I have patches for this improvement in my user repository in the branch
 `use_gmp`: https://gitweb.torproject.org/user/phw/obfsproxy.git

 Note that the patch requires the module `gmpy` which is '''not''' part of
 Python's standard library.  Debian knows the package as `python-gmpy`.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/10031>
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