Also referred to as a Type I, this is a remailer that accepts messages
encrypted with its publicly available PGP key. PGP is Pretty Good
Privacy, the well-respected public-key encryption program which is
widely available and, with a few exceptions, freeware. Users encrypt
their clear-text, outgoing message with the Cypherpunk remailer's
public key. This can be done with any text editor like Notepad and a
properly installed version of PGP. There is a particular message
format to follow, one that the remailer software can understand:

============ 
::
Anon-To: news.reporter@nbc.com
Latent-Time: +0:00

##
Subject: My Company Dumps Toxic Waste

I'm writing this anonymously because I don't want to lose my job.
My company has, for the past three years... 
============ 

The above message is cut and paste into PGP and encrypted with the
chosen remailer's key, say gretchen@neuropa.net

============ 
-----BEGIN PGP MESSAGE-----

Version: PGP 2.6x
hQCMA8asoPEC0e2BAQP9GqR2aXNOstRq8eJW2QVubioR0gO7Ue0AOL/rFdnxXknC
YPpe2X2TKlcvd961+lhe9w2Y8vo3JcBYYBifTJRwmMjnXLagCU4Mhh0VZtk/QXMZ
/FLeJWi67qsb45a2mNw0/Q8eXHKfOQyHcmEQ7cg/bq4Xz6LusfxBHF8zsojVOgal
8RVRtr9drjBlOzJvWxaq7LrKidME6q0tM7pRiLN5dvVBon2NKlmpJI6vAFjyi8ma
f5Bg6Zor+PMxcm3EmuWbjLEiOu5USrTgU4OiaC7PHF9INxwXuKmdNz/JprgOc0c6
6s6RvbOo6rsvlwqPKw==
=ICz/
-----END PGP MESSAGE-----
============= 

Finally, the user has to append a directive to the top of the
encrypted message, making it look like this:

============ 
::
Encrypted: PGP

-----BEGIN PGP MESSAGE-----
Version: PGP 2.6x 

hQCMA8asoPEC0e2BAQP9GqR2aXNOstRq8eJW2QVubioR0gO7Ue0AOL/rFdnxXknC
YPpe2X2TKlcvd961+lhe9w2Y8vo3JcBYYBifTJRwmMjnXLagCU4Mhh0VZtk/QXMZ
/FLeJWi67qsb45a2mNw0/Q8eXHKfOQyHcmEQ7cg/bq4Xz6LusfxBHF8zsojVOgal
8RVRtr9drjBlOzJvWxaq7LrKidME6q0tM7pRiLN5dvVBon2NKlmpJI6vAFjyi8ma
f5Bg6Zor+PMxcm3EmuWbjLEiOu5USrTgU4OiaC7PHF9INxwXuKmdNz/JprgOc0c6
6s6RvbOo6rsvlwqPKw== 
=ICz/
-----END PGP MESSAGE-----
============ 

The user then mails the above encrypted message (double colons and
all) NOT to the intended recipient but instead to the remailer's
address: <gretchen@neuropa.net>. This arrives at the remailer where it
is eventually processed, decrypted and mailed to
<news.reporter@nbc.com> appearing to have come from "Anonymous"
<nobody@neuropa.net>.

Most remailers are not purely Cypherpunk but will accept both
Cypherpunk and Mixmaster messages. Keep in mind too that there are
currently only a few Cypherpunk (Type I) remailers that will accept
non-PGP messages and their numbers are dwindling.

See also:

This tutorial with pictures and step by step instructions
<http://anon.xg.nu/shotsof.htm>.

Read some history about how Cpunk remailers first came about
<http://cryptome.org/zks-v-tcm.htm>.

Visit this link at LCS.MIT.EDU about remailers and their importance
<http://www.lcs.mit.edu/impact/perspect/perspective?name=9901>.