Re: end-to-end encryption question

[Scott Bennett <bennett@xxxxxxxxxx>]

     On Thu, 13 Sep 2007 11:46:33 +0200 Peter Palfrader <peter@xxxxxxxxxxxxx>
wrote:
>On Thu, 13 Sep 2007, Scott Bennett wrote:
>
>>      For obvious reasons, tor should not be getting directory information over
>> a connection that is not encrypted from end to end, even if everyone knows
>> exactly what the content of the directory information happens to be at any
>> given moment.
>
>What are those reasons?  I'm sorry they are not apparent to me.
>
     Well, when I wrote that, one thing that was worrying me was a MITM attack.
After sending it, I remembered that the directory information would be signed
by an authority, which should infinitesimalize any chance of a MITM corruption
of the information going undetected.  But that still leaves open a somewhat
less dangerous situation in which the MITM always damages the information or
interferes with the connection somehow, creating a form of DoS, so that the
recipient cannot obtain valid directory information.  That would be a type of
DoS that would not, for example, trigger any alarms in a router or other
typical network monitor.
     There may also be some kind of profiling attack made possible simply by
observing the timing of when a tor gets directory updates, network status
documents, etc., though I haven't a good approach in mind for doing that.
     There was another fleeting thought or two, but they evaporated while I
was typing my original message on the matter.  If any come back to mind and
still seem interesting, I'll post them.
     It may be that there is no real threat here and that I simply engaged
fingers before engaging brain, but I've always had a dislike for the
possibility of being watched without my knowledge or permission.


                                  Scott Bennett, Comm. ASMELG, CFIAG
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