[messaging] Tor Hidden Services in (Cables, SMTorP, Pond)

[elijah]

On 06/17/2014 02:02 PM, Trevor Perrin wrote:
> On Mon, Jun 16, 2014 at 11:18 AM, elijah <elijah at riseup.net> wrote:

>> Mix networks are not without their own problems [1], but there is much
>> room for improvement, depending on the tolerance for delay.
> 
> I think that paper is about problems with "threshold mixes" which fire
> once they've received a certain # of messages; and doesn't affect
> "timed" or "stop-and-go" mixes, which seem the more obvious approach.
> But I'm no expert here.

Yeah, the paper says limitations described don't apply to timed mixes.

> The security of a mix doesn't depend on having so many parts it's hard
> to observe them, it depends on the time delays and the number of users
> your traffic is being "mixed" with.  Sending traffic through a single
> trusted mix, or a "cascade" of mixes run by a few different
> organizations, could be very effective.

On a related note, postfix already supports an option to spool messages
for a particular transport for a configurable number of seconds (after
which they are delivered in a burst). By setting this option on a
per-domain basis, I think you could achieve some very rudimentary
measures against timing analysis. The question is then, given the
average number of messaged delivered to a particular domain every
minute, what should the wait period be for that domain? This is not a
mix at all, but could be super easy and still of significant benefit.

-elijah