ANONYMOUS REMAILERS


QUESTION: What is an Anonymous Remailer and why would I use one?

ANSWER: For most of us, posting a message to a Usenet newsgroup carries with it much less privacy than we expect. Even though a message may appear in the newsgroup for only a matter of days, some current Internet search engines, such as Deja News, permit searches of Usenet messages over the past several years. The results of these searches can list and show every message sent from a particular e-mail address. It would be easy to imagine sensitive situations in which Usenet participants' written views on controversial topics can be used against them years after they are posted.

Similar concerns may be shared by persons who participate in support groups via e-mail. Participants in such groups must send and receive e-mail messages to and from each other, but given the sensitive topics discussed they may wish to retain their anonymity.

Simple methods of hiding the source of a message such as configuring an e-mail or news reader computer program to provide an anonymous "return to" address are ineffective as the Internet message delivery system adds a "header" to each message that includes information regarding the source of the message.

An Anonymous Remailer can be used to hide this source information. The Anonymous Remailer will strip the return address information from a message, add a computer generated code as a return address and then remail the message from its own server. The effect of this is that the recipient receives a message from an anonymous user name at the Anonymous Remailer's domain. In many cases, the Anonymous Remailer maintains the original return address information so that return mail may be forwarded to the original sender.

Using an Anonymous Remailer provides a greater degree of anonymity than sending a standard Usenet message, but it is not foolproof. The operator of a well known Anonymous Remailer in Finland was forced by Finnish police and court order to disclose the identity of a user in connection with litigation involving the Church of Scientology. The user allegedly sent messages to newsgroups that included materials infringing copyrights held by the Church of Scientology.

For additional security, messages may be forwarded from one Anonymous Remailer to another, or several, before delivery to its ultimate addressee. Messages can also be encrypted in layers so that in each step along the chain of Anonymous Remailers only the next recipient is known. While still not foolproof, the discovery of a particular sender's identity could require disclosure by multiple Anonymous Remailers. In the alternative, Anonymous Remailers that do not retain any of the original message information can provide an even higher level of security. Discarding the original message information, however, precludes return mail to an anonymous sender or assignment of the same anonymous address to a sender's subsequent messages.

It should be noted that if an Anonymous Remailer is used, senders should disable any automatic signature feature in their e-mail programs. All of the precautions of a carefully sent anonymous message may be useless if the body of the message includes the sender's name, e-mail address or other information.

A list of Anonymous Remailers can be found in Raph Levien's web site at http://http.cs.berkeley.edu/~raph/remailer-list.html. Jim Black can be reached at jimb@jrb.com.


© James R. Black 1997
applet by New Media Marketing Lab at Sun Microsystems, Inc.