nymble blocking system_need
DESCRIPTION
This is a presentation for seminar for B.Tech. This paper is a IEEE topicTRANSCRIPT
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Introduction Nymble Properties The Nymble System Security Model Disadvantages Conclusion
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Anonymous network eg: Tor
IP hiding facilities Users misuses this network for abuse They deface popular websites Websites cannot blacklist individual malicious
users IP address They blacklist entire anonymizing network
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In pseudonymous credential systems Users are added to a blacklist This weakens the anonymity
In anonymous credential system Group signatures Lacks scalability
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Nymble is a system that allows websites to selectively blacklist users of anonymizing networks such as Tor without knowing the user's IP-address. Users not on the blacklist enjoy anonymity while blacklisted users are not allowed future connections for a duration of time while their previous connections remain unlinkable. Since Nymble allows websites to blacklist anonymious users of their choice, and since users are notified of their blacklist status, Nymble gives websites the power to define their own definition of "misbehavior"
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Properties
Anonymous Authentication
Backward Unlinkability
Subjective Blacklisting
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Fast Authentication Speeds
Rate-Limited Anonymous Connections
Revocation Auditability
Sybil attack
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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 remain unlinkable. Servers can therefore blacklist anonymous users without knowledge of their IP addresses while allowing behaving users to connect anonymously.
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Fig. The Nymble system architecture showing the various modes of interaction
Resource-Based Blocking To limit the Sybil attack the Nymble
system binds nymbles to resources that are sufficiently difficult
to obtain in great numbers.
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The Pseudonym Manager The Nymble Manager Blacklisting a User
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Notifying the User of Blacklist Status
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Nymble aims for four security goals. Blacklistability Rate-limiting assures Nonframeability Anonymity
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Nymble is comprehensive credential system. Add a layer of accountability to any publicly known
anonymizing network. Servers blacklist misbehaving users maintaining their
privacy. Increase the mainstream acceptance of anonymizing
network.
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www.wikipedia.com www.seminarprojects.com www.airccse.org www.torproject.org
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System Setup
ServerRegistration
BlacklistUpdateAndComplaining
Tor