General information

A Cypherpunk Remailer (also type I Remailer) is an anonymizating Remailer, which kryptierte or unencrypted message assumes and passes on. Here the Remailer before the forwarding of the message removes if possible all information, which suggests the origin and the sender.

The Cypherpunk Remailer is a server software, which makes the anonymizated forwarding service and to messages available finished, which were drawn up in the correct format; one speaks also of Cypherpunk minutes.

The messages themselves, typically E-Mail or contributions for Usenet, are addressed to the final receiver or a Usenet forum. The E-Mail program of the sender is ideal-proves so adjusted that it dispatches all message mandatorily to the Remailer. This can on the same computer, on a computer in the local area network (LAN) or on a computer in the Internet to be installed.

Origin and development

Beginning of the 90's sketched an cryptography-interested group of Internet users, who called themselves Cypherpunks, the model of a Remailers. They integrated some the suggestions of David Chaum.

In the future different Remailer programs, under it also different server types, developed themselves which were common the support of Cypherpunk minutes, those however distinctive with respect to details time strongly. With the introduction of newer algorithms to coding software, new PGP versions and - derivatives and particularly by the experiences, which were made with the enterprise of the Remailer, to have also in handling coding of differences result. Temporarily it came to between Remailern.

Method

Before the forwarding of a message by the Remailer the message header in such a way specified is modified and the sender-referred information is removed. The final receiver of a in such a way treated E-Mail receives those of the Remailers as only indication of sender.

Extensions

Some the techniques for the security of E-Mail traffic, found with all Remailer types, for Cypherpunk Remailer were already introduced. The sender of a Remailer message steers to a large extent, as its E-Mail is treated by the Remailernetz. Some possibilities:

<li> concatenation of several Remailer, in order to make it also for operators of the Remailerdienste or hearing aggressors not possibly, the anonymous communication partners too the messages and the receiver information with PGP or GnuPG, also between the Remailern of a and removing from coincidence data, in order the identification of a message by their variable too vereiteln.<li>Zwischenlagern from messages about arbitrary time intervals (normally until maximally 1 day), in order to work against the analysis of communications.

Proceeding (exemplary)

1. Message write
2. The text place additional lines in front:
   Anon ton: remailer@cypherremailer.de
3. This text is usually coded with the public key of the Remailers.
4. If the coding is selected, the Remailer receives over it to information as the coded message part the information is placed in front:
   Encrypted: PGP
5. Depending upon number of concatenated Remailer the last steps repeat themselves.

Attacks against the Cypherpunk Remailer

Cypherpunk Remailer have some weak points.

Many messages are continued to send away immediately after receipt with the Remailer. If now an aggressor can pursue the traffic of the Remailer, then it is possible for him, messages temporally as to be assigned and close thus on receivers and senders also due to its size.

The moreover the aggressor could intercept a message and bring these in purposefully again into the system. If this rebringing in should take place in large number, an aggressor can likewise find the path out to the receiver.

Both problems were recognized by Lance Cottrell and described in the essay "“mix master & Remailer Attacks"”.

Cypherpunk Remailer can be combined with a mix master, the message of the Cypherpunk Remailers works over again. The security of the system profits then from general as safe and durable outstanding mix master minutes.

See also

• Remailer, mix master Remailer, Nym Remailer
• Anonymity in the Internet, Anonymizer
• Gate

Literature

• E-Mail Security, Bruce Schneier (ISBN 0-471-05318-X)
• Computer Privacy Handbook, Andre Bacard (ISBN 1-56609-171-3)

Related links

• Mix master & Remailer Attacks
• A of remailer FAQ
• Remailer Vulnerabilities
• Anonymous E-Mail over Remailer (FAQ)
• Anonymous dispatch by enamels and Usenet Postings

Articles in category "Cypherpunk Remailer"

We found here 31 articles.

Related Websites

We found here 4 related websites.

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• [FAQ 3.3] What is a Cypherpunk Remailer
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