[tor-bugs] #7202 [Tor]: Implement ntor handshake or its successor

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#7202: Implement ntor handshake or its successor
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 Reporter:  karsten             |          Owner:                    
     Type:  project             |         Status:  needs_review      
 Priority:  normal              |      Milestone:  Tor: 0.2.4.x-final
Component:  Tor                 |        Version:                    
 Keywords:  SponsorZ tor-relay  |         Parent:                    
   Points:                      |   Actualpoints:                    
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Comment(by nickm):

 Replying to [comment:7 mikeperry]:
 > I started checking that the unit tests match the ntor paper's page 16,
 and I noticed what looks like a serious issue: In
 onion_skin_ntor_server_handshake(), it seems you omit step 9, the
 identity-element check on X.
 >
 > Oh wait, hah! I just checked the client side in
 onion_skin_ntor_client_handshake() and saw "XXXXX VERIFY Y IS NOT POINT AT
 INFINITY". So it looks like you're aware of it. But damn, we better add a
 matching comment in onion_skin_ntor_server_handshake() too. Probably also
 a log message or something until we fix the XXXX. Otherwise the old 2007
 DH bug could sneak back in again :(.
 >
 > I have a bunch more questions and comments, but this seemed pressing
 enough that it needed to be written down ASAP.

 This was discussed a lot on the tor-dev thread, and I discussed it more
 with Ian, Douglas, and Brekant.  It isn't necessary.

 At Ian's suggestion, I added a set of tests to ensure that the output of
 the various EXP() operations wasn't the point at infinity. I'm not sure
 they're needed, but they oughtn't hurt assuming I did them in the non-
 stupid way. (Which I believe I did.)

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/7202#comment:9>
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