International Journal of Advanced Research in Computer Science and Software Engineering (IJARCSSE)
The authors present a secure system called Nymble, which provides all the following properties: anonymous authentication, backward unlinkability, subjective blacklisting, fast authentication speeds, rate-limited anonymous connections, revocation auditability (where users can verify whether they have been blacklisted), and also addresses the Sybil attack to make its deployment practical. In Nymble, users acquire an ordered collection of nymbles, a special type of pseudonym, to connect to Websites. Without additional information, these nymbles are computationally hard to link, 4 and hence, using the stream of nymbles simulates anonymous access to services. Web sites, however, can blacklist users by obtaining a seed for a particular nymble, allowing them to link future nymbles from the same user - those used before the complaint remains unlinkable.