A type II remailer protocol. Also, according to the authors, the most popular software implementation of that protocol. The current version is 2.9 which is stable. Beta versions of the 3.0 version are also available but still in beta stage at this time of writing (January 2007).
- Cypherpunk - A primitive type I remailer network implementation.
- Mixminion - A nextgen type III remailer network implementation.
- The Onion Router - Mixnet for other network protocols.