Cryptography Reference
In-Depth Information
would recognize the MIME type “X-Anon-To:” and resend the mail
immediately.
To a large extent, these tools are not the most important step. The
tools are only useful if the remailer owner is willing to resist calls to
reveal the hidden identity.
There is also a great need for anonymous dating services on the
Net. Although many of the remailers are clothed in the cyberpunk
regalia, there is no doubt that there are many legitimate needs for
remailers. An upscale, mainstream remailer could do plenty of busi-
ness and help people in need of pseudonymous communication.
10.10 Summary
The Disguise
The path between sender and recipient is hidden from
the recipient by having an intermediate machine remove the
return address. More sophisticated systems can try to obscure
the connection to anyone who is watching the mail messages
entering and leaving the remailing computer.
How Secure Is It?
Basic anonymous remailers are only as secure as
the strongest link along the chain of remailers. If the person
who runs the remailer chooses to log the message traffic, then
that person can break the anonymity. This may be compelled
by the law enforcement community through warrants or sub-
poenas.
The more sophisticated remailers that try to obscure traffic
analysis can be quite secure. Anyone watching the network of
remailers can only make high-level statements about the flow
of information in and out of the network. Still, it may be quite
possible to track the flow. The systems do not offer the un-
conditional security of the dining cryptographers networks de-
scribed in Chapter 11.
Digital Mixes must also be constructed correctly. You cannot
use RSA to sign the message itself. You must sign a hash of the
message. [PP90] shows how to exploit the weakness.
How to Use the Software
The Cypherpunks archive offers all of the
software necessary to use chaining remailers orMixmaster. The
WWW pages are the easiest options available to most people.
