Re: Security of coalesced packets

[Mikkel Fahnøe Jørgensen <[e-mail]>]

In the current design, you need to use the long header to coalesce
(the trailing packet can use the short header). And packets with the
long header only appear during connection setup.

The thing is that any MitM can add a long header at any point in time. So
long headers can appear throughout the connection alhough not a meaningful.
For the same reason it is also easy to disallow later in the connection,
but it isn’t.

I get you point about other signals in rate and IP headers. The IP headers
could be monitored and are less likely to be abused - but my knowledge is
limited here. Of course unexpected long headers could also raise a flag,
but disallowing would be simpler.

Traffic rate signalling is hard to avoid, it is known that THOR traffic is
identified this way, albeit based on the inherent traffic pattern of the
original user. (Which is also why I’m dubious about trying so hard to avoid
linkability).