[tor-bugs] #17694 [Tor]: Hash PRNG output before use, so that it's not revealed to the network

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#17694: Hash PRNG output before use, so that it's not revealed to the network
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 Reporter:  teor         |          Owner:
     Type:  enhancement  |         Status:  needs_review
 Priority:  Medium       |      Milestone:  Tor: 0.2.8.x-final
Component:  Tor          |        Version:  Tor: unspecified
 Severity:  Normal       |     Resolution:
 Keywords:               |  Actual Points:
Parent ID:               |         Points:
  Sponsor:               |
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Comment (by teor):

 Replying to [comment:9 nickm]:
 > feature17694_strongest_027 starts this, based on the code for #17686.  I
 suggest it for inclusion in 0.2.8 only.  I'm going to extend it to know
 about other prngs.

 This patch only hashes the entropy used in keys.

 I don't think this achieves the overall goal: "make sure we never leak raw
 PRNG output to the network".

 We can easily leak raw PRNG output via salts, nonces and other randomly
 chosen values that are sent on the wire.

 Even our "random" choices of relays could leak some bits.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/17694#comment:12>
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