Categories: anonymitypseudonymityhidedissociate

Psuedonymous Identity


Hide the identity by using a pseudonym and ensure a pseudonymous identity that can not be linked with a real identity during online interactions.


This pattern can be used for systems in which users are identified by public identities.


Many kinds of sensitive informations are released through web interactions, email, data sharing or location-based systems, which can contain the name of a user or header information in packets. Another problem could be to interact anonymously in a forum. However too much interaction in a forum with an anonymous identity can be dangerous in the sense that the relation between original identity and a pseudonymous identity can be exposed.


Initiate a random pseudonym, that can not be related to the original, so that the identity is hidden. Furthermore a pseudonym depends on concealment, so the pseudonym allocation needs protection.

Hide the identity of the participants.


The real identity of a user is hidden. In certain scenarios there is a need for additional space to store the pseudonym-identity mapping. Extensive Usage of the same pseudonym can weaken it.


Assuming some students are writing an exam and they have to fill out a form about their identity, where there is an optional field for a chosen pseudonym. This way the result can be released under the chosen pseudonyms and the identity of each student is hidden. But by being observant, some students might be able to figure out which identity belongs to which pseudonym and so the confidentiality of the identity is compromised.

[Known Uses]

Anonymizer are well-known tools for anonymous web interactions. They work for example by using a proxy between a request sender and a recipient to strip header information like HTTP_USER_AGENT in packet headers because they contain metadata about packet senders. The Mixmaster is an anonymous remailer that hides the sender and recipient identity by stripping its name and assigning a pseudonym. Some data sharing systems with a privacy-preserving focus make use of pseudonyms so that identifying information such as names and social security numbers are hidden. For example various electronic healthcare systems are using pseudonyms for the storage of e-health records.