'Today' considers data retention and IMP

[Paul Jakma]

On Mon, 12 Jan 2009, Igor Mozolevsky wrote:

> Both methods are still susceptible to inference. In the first one, 
> if, say, every time smtp.your-isp.co.uk connected to 
> smtp.evil-doer.org was preceded only by you connecting to 
> smtp.your-isp.co.uk one could infer that you were the cause of the 
> connections to smtp.evil-doer.org.

Your-ISP.co.uk will be logging details of the message, and will 
(without question) co-operate with LEAs under RIPA if asked. So 
whether Your-ISP.co.uk uses TLS on MTA-MTA connections or not is 
quite irrelevant, if we're worried about spying by a police-state at 
least.

> In the second case, message envelope is still plaintext, so while 
> the interceptors may not know the contents of the message, they do 
> know whom the message is going to, the subject line and the size of 
> data you are sending.

That could be a problem for anyone smart enough to encrypt the body 
but stupid enough to incriminate themselves in the Subject, yes. :)
(Pedantry: The subject is not part of the envelope..)

The inter-communication information does get leaked, yes. That should 
be less sensitive than the actual content of messages though. I guess 
there are ways to obscure it too, but I don't know.

regards,
-- 
Paul Jakma	paul@clubi.ie	paul@jakma.org	Key ID: 64A2FF6A
Fortune:
No matter where I go, the place is always called "here".