There's also a second aspect of "identifiability" relating to "traffic 
analysis" that I think may not be well-developed, and perhaps there's a better 
term for the concept. Can a given packet or flow of packets intercepted by an 
intermediary be examined to tell the intermediary what kind of traffic is 
present, or even what protocol is being used? One might consider this as part 
of "traffic analysis", but it might be useful to give specific guidance beyond 
"use TOR."

For example, does the protocol used a fixed token at a fixed offset within the 
packet (such as a protocol number) to indicate the protocol of the packet? Does 
it use constant data packet sizes and timing that indicate a real-time flow as 
opposed to a file transfer?  One might consider this "unlink ability at the 
packet level", but I suspect it's subtly different from the primary usage of 
unlink ability.

Another undeveloped concept is how does the protocol in question contribute to 
the privacy of other protocols simply by being used. For example, if we have 
lots of different protocols that have similar entropy levels and lack 
distinguishing marks, it's harder for an intermediary to guess which type a 
particular packet is. We're also missing the concept of entropy (for which 
"more" is generally "better", from a privacy perspective) from the whole 
discussion.


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