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Re: Anonymity: A Modest Proposal

Modemac writes:
> The basic idea for this system goes like this:
>      1) A person writes a message and encrypts it with PGP.
>      2) That person then posts his message to the "anonymous messages"
>         newsgroup.
>      3) A remailer scanning the newsgroup picks up the message,
>         decrypts it, strips the headers and makes it anonymous, and
>         sends it to its destination.

Just for the record, I'll note this is a fairly old idea (cf. the 
Cyphernomicon, news:alt.anonymous, news:alt.anonymous.messages, etc.)

> A "token" (like the token ring of IBM fame) would be passed back and
> forth between all of the Cryptoclients in the remailer network, so
> that only one remailer would be "active" at any given time.  This
> token would be passed back and forth at random, so no one would know
> exactly which remailer is being used to anonymize a message.

I don't see how this is possible given widespread RFC 822 compliance. 
Any given message must be sent from some particular address. I see two 
main options:

(1) The remailed-message is sent as a single message from a single remailer.
    That remailer is subject to various sorts of pressure if the remailed-
    message offends its recipient.

(2) The remailed-message is sent as several messages from several remailers.
    The recipient's MDA reassembles the fragments into the remailed-message.
    Any or all of those remailers are subject to pressure if the remailed-
    message offends the recipient.

Either way, at least one remailer is subject to pressure for sending a 
specific piece of email.

(If the token is passed around randomly, then it might be more difficult for 
an adversary to predict which remailer will send the _next_ message. However,
adversaries such as Cof$ are interested in assailing remailers that have
_already_ sent messages, due to the content of those messages. They can tell 
which remailer sent _past_ messages, which is what they need.)  

-Futplex <[email protected]>