We are interested in the development of privacy-friendly technology supporting anonymity and pseudonymity on the Internet.
Organizations know the users only by pseudonyms.
Different pseudonyms of the same user cannot be linked. A main part of the service is a 'pseudonym authority' which is accessible over the Internet and which grants users 'pseudonym credentials' which they can then use to anonymously access web servers. The granting and use of the pseudonym credentials are defined in a new, provably secure pseudonym system, which guarantees unlinkability and anonymity of the different actions of a user, even when using the same credential several times, and even towards the pseudonym authority. Anonymous Multi-show Credential System with Optional Anonymity Revocation. Efficient anonymous fingerprinting with group signatures.