Re: Long-Lived Remailers

At 3:00 PM 5/21/96, Rev. Mark Grant, ULC wrote:
>On Tue, 21 May 1996, Timothy C. May wrote:
>
>> Traffic analysis will be quite easy to do, of course, as all mail sent to
>> the persistent address comes out of the "disposable@foo.com" address.
>> Q.E.D.
>
>Yeah, but the attack model I was assuming was lawyers rather than
>intelligence agencies. The NSA could probably easily link the two
>together, but the Church of Foobar(tm) probably couldn't. They'd only have
>access to the logs on the ISP and the information you gave when you signed
>up, not the raw packets on the Net.

The traffic analysis on this fixed mapping system needs no access to
packets and is childishly simple.

Let's call the first site "Alice" and the emanation site "Bob."

That is, all messages sent to the persistent site Alice appear to come from
the site Bob.

The Church of Clams can simply send messages addressed to themselves
through the Alice remailer and see immediately that they appear to come
from Bob.

Q.E.D.

--Tim May

Boycott "Big Brother Inside" software!
We got computers, we're tapping phone lines, we know that that ain't allowed.
---------:---------:---------:---------:---------:---------:---------:----
Timothy C. May              | Crypto Anarchy: encryption, digital money,
tcmay@got.net  408-728-0152 | anonymous networks, digital pseudonyms, zero
W.A.S.T.E.: Corralitos, CA  | knowledge, reputations, information markets,
Licensed Ontologist         | black markets, collapse of governments.
"National borders aren't even speed bumps on the information superhighway."

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> That is, all messages sent to the persistent site Alice appear to come from
> the site Bob.
> The Church of Clams can simply send messages addressed to themselves
> through the Alice remailer and see immediately that they appear to come
> from Bob.

But this does not prove that _all_ messages from Bob came from Alice. The
only messages the Church can prove went through Alice, are the messages
they themselves sent through Alice. 

It would not help the Church to say "We know our trade-secret Mystical
Clam Chowder Recipie went through the Alice remailer, because we sent it
through that remailer ourselves." Also, Alice could also demonstrate
sending a message through Bob without using the Alice remailer at all. 

I am assuming that in this hypothetical situation, remailers themselves
are not illegal, but the owners are held responisble for what goes through
them. I am also assuming that Bob does not have any records that show the
offending message coming from Alice. 


=====================================================================
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| Email: steve@edmweb.com   Home Page: http://www.edmweb.com/steve/ |
| PGP (2048/9F317269) Fingerprint: 11C89D1CD67287E68C09EC52443F8830 |
|          -- Disclaimer: JMHO, YMMV, TANSTAAFL, IANAL. --          |
===================================================================:)

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On Tue, 21 May 1996, Timothy C. May wrote:

> At 3:00 PM 5/21/96, Rev. Mark Grant, ULC wrote:
> >On Tue, 21 May 1996, Timothy C. May wrote:
> >> Traffic analysis will be quite easy to do, of course, as all mail sent to
> >> the persistent address comes out of the "disposable@foo.com" address.
> >> Q.E.D.
> >
> >Yeah, but the attack model I was assuming was lawyers rather than
> >intelligence agencies. The NSA could probably easily link the two
> >together, but the Church of Foobar(tm) probably couldn't. They'd only have
> >access to the logs on the ISP and the information you gave when you signed
> >up, not the raw packets on the Net.
> 
> The traffic analysis on this fixed mapping system needs no access to
> packets and is childishly simple.
> 
> Let's call the first site "Alice" and the emanation site "Bob."
> 
> That is, all messages sent to the persistent site Alice appear to come from
> the site Bob.
> 
> The Church of Clams can simply send messages addressed to themselves
> through the Alice remailer and see immediately that they appear to come
> from Bob.

	Randomize the output remailer? Sometimes Alice exits Bob,
Sometimes Charlie, sometimes Tom etc. 


Petro, Christopher C.
petro@suba.com <prefered for any non-list stuff>
snow@crash.suba.com