[tor-bugs] #5598 [Tor Relay]: Turn DynamicDHGroups off by default

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#5598: Turn DynamicDHGroups off by default
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 Reporter:  rransom      |          Owner:     
     Type:  enhancement  |         Status:  new
 Priority:  minor        |      Milestone:     
Component:  Tor Relay    |        Version:     
 Keywords:               |         Parent:     
   Points:               |   Actualpoints:     
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Changes (by mikeperry):

 * cc: marsh@… (added)


Comment:

 I think choosing a random "prime" chosen from available primes of the same
 bitwidth is better for PFS, assuming the apache prime passes the same
 level of known primality tests as our ad-hoc primes pass, and also
 assuming that these primatilty tests are actually valid.

 The reason I think ad-hoc primes are better for PFS is because of the
 possibility of time-space tradeoff attacks against specific prime groups.
 Seems plausible to me that certain small-ish prime groups might have
 precomputed tables to expedite the discrete log.

 Maybe DH-1024 is too big for these types of attacks, but hey, I'm not the
 one who thinks it's actually useful to build a datacenter in Utah to
 record all data for future cryptanalysis.

 Also note: I am not a cryptographer. I just play one on tv.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/5598#comment:10>
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