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Cypherpunk anonymous remailer

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A Cypherpunk anonymous remailer, also known as a Type I remailer, is a type of anonymous remailer that receives messages encrypted with PGP or GPG, follows predetermined instructions to strip any identifying information, and forwards the messages to the desired recipient.[1]

Cypherpunk anonymous remailers are susceptible to traffic analysis attacks, exploiting the fact that messages sent to such remailers are then sent to the recipient in the order they were received, making it possible to identify who sent which message. This weakness has motivated the development of Type II and Type III remailers.[2] Before Mixmaster or Type II remailers, a solution to this problem was to send mail in batches;[3] alternatively, multiple remailers could be used in sequence to obfuscate the sender's identity further.[4]

When Type II remailers came into existence, they built upon the technology of Type I remailers. This made Type I remailers mostly obsolete.[5] However, there are still websites and systems that rely on this general idea of layered encryption and identity obfuscation.[6]


While they are mostly considered obsolete due to the Mixmaster being the most common remailer type,[7] cypherpunk remailers are still applicable in niche applications for those who have no other accessible options. For example, sites that are censored or blocked by governments can use remailers to circumvent the censorship. Cypherpunk remailers require less setup and fewer resources to run, and can therefore be a suitable solution for those with few assets or little time to spare.

See also[edit]


  • The additional headers used in this context are referred to as 'pseudo-headers' because they are not included in the RFC 822 headers specification for email.
  • Messages sent to cypherpunk remailers can be layered, meaning they pass through multiple cypherpunk remailers to minimize the chances of identifying the sender.
  • Some cypherpunk remailers also function as Mixmaster anonymous remailers, enabling them to divide long cypherpunk messages into Mixmaster packets and forward them to the next remailer if it supports Mixmaster functionality.
  • Many users of cypherpunk remailers may choose to repeat steps 1-4 to add additional layers of protection to their messages, routing them through multiple remailers for enhanced privacy and security.

Further reading[edit]

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

External links[edit]


  1. ^ "Anonymous Remailers". mason.gmu.edu. Retrieved 2023-12-11.
  2. ^ Van Oorschot, Paul C. (2 March 2023). "Anonymous remailers + secure email" (PDF). Archived from the original (PDF) on 2023-12-31.
  3. ^ Anonymous Remailers. (n.d.). Retrieved August 10, 2023, from [1]Archived 2021-09-24 at the Wayback Machine
  4. ^ Remailers: Send Emails without Registration. (n.d.). Retrieved August 10, 2023, from [2]Archived 2023-06-09 at the Wayback Machine
  5. ^ Winkler, S., & Zeadally, S. (2015). An analysis of tools for online anonymity. International Journal of Pervasive Computing and Communications, 11(4), 436–453. [3]Archived 2023-08-13 at the Wayback Machine
  6. ^ Lutkevich, Ben (April 2021). "What is Obfuscation?".
  7. ^ "Mixmaster anonymous remailer", Wikipedia, 2024-04-10, retrieved 2024-06-20