Extended Nymble: Method for Tracking Misbehaving Users Anonymosly while Blocking

We have many of anonymizing networks which provide users to access services of server anonymously. Anonymity has received increasing attention in the literature due to user awareness of their privacy. Nowadays, anonymity provides protection to users to enjoy network services without being traced. Anonymizing networks such as Tor allow users to access Internet services privately by using a series of routers to hide the client's IP address from the server. Web site administrators routinely rely on IPaddress blocking for disabling access to misbehaving users, but blocking IP addresses is not practical if the abuser routes through an anonymizing network. As a result, administrators block all known exit nodes of anonymizing networks, denying anonymous access to misbehaving and behaving users alike. To address this problem Nymble is developed, a system in which servers can "blacklist" misbehaving users. We present extensions to nymble framework for anonymizing blacklisting schemes. First, we provide a mechanism to nymble manager to track blacklisting of user in multiple linking windows while preserving anonymity of the users. Some users always look to misbehave with servers; there major intention is to make the server down. The problem with nymble is nymble manager blacklist a user for one likability window (i.e. 1 day), on the other day again he can misbehave with same server or other server. He can continue it as his everyday activity as Nymble manager doesn't have any mechanism to identify such type of users while preserving anonymity. To address this problem, we present a method which can identify such users, while preserving anonymity and nymble manager with identified information can decide upon how much time to blacklist a misbehaving user. We also suggest some algorithms which are changed in comparison to existing nymble.