A messaging service is enhanced by using a trusted third party to exchange the identifiers of the communication partners by pseudonyms.
This pattern can be used for online communications by email, through message boards, and newsgroups.
Messaging includes all forms of communication through emails, articles, message boards, newsgroups etc. This information could be stored and used to build sophisticated user profiles. Sometimes it can also be used to prosecute people.
A message is send by a user to the server, which exchanges the sender's address with a pseudonym. Replied messages are sent back to the pseudonymous address, which will then be swapped back to the original.
The goal of this pattern is to prevent unforeseen ramifications of the use of online messaging services.
Users can communicate more freely. Pseudonym servers can be misused to send offensive messages, for spam mails or by criminals for illegal activities. Under those circumstances it could be necessary to revoke the pseudonymity of the corresponding parties.
Alice is a political activist and tries to organize a political demonstration. Since her government does not like free speech, her communication channels are intensely monitored and one day, she simply disappears into a labor camp and is never seen again.
nym.alias.net a pseudonymous email system with the goal to provide secure concealment of the user's identity. A Type I Anonymous Remailer forwards emails by modifying the message header and removing sender-related information.