nymble: blocking system
Post on 25-May-2015
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1
WELCOME
NYMBLE BLOCKING SYSTEM
Manzeer Fasaludeen
Roll No: 09412007
S7 CS, SHMEC
CONTENTS
Introduction Nymble Properties System Architecture Security Model Limitations Conclusion
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INTRODUCTION
Anonymous networko IP hiding facilitiesoPolipo, Tor, USAIP
Users misuses this network for abuse They deface popular websites Websites cannot blacklist individual IP
address They blacklist entire anonymizing network
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Current Strategy
In pseudonymous credential systems Users are added to a blacklistWeak in anonymity
In anonymous credential systemGroup signaturesLacks scalability
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NYMBLE A system that allows websites to selectively
blacklist users of anonymizing networks. Blocks user without user's IP-address. Legitimate users enjoy anonymity. Blacklisted users got blocked for future
connections. Previous connections remain unlinkable.
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FEATURES
Anonymous Authentication
Backward Unlinkability
Subjective Blacklisting
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FEATURES
Fast Authentication Speeds
Rate-Limited Anonymous Connections
Revocation Auditability
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THE NYMBLE SYSTEM
User
The Pseudonym Manager
The Nymble Manager
Server
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SYSTEM ARCHITECTURE
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Fig. The Nymble system architecture showing the various modes of interaction
BLACKLISTING USER
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Fig: The Nymble system architecture showing how a user is blacklisted
Cont…
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SECURITY MODEL
Aims four security goals
Blacklistability
Rate-limiting assures
Nonframeability
Anonymity
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LIMITATIONS
Sybil attack Mimics IP based blocking Availability of multiple IP address helps
users circumvent the system
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CONCLUSION
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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REFERENCES
www.airccse.org www.torproject.org www.sciencedirect.com www.wikipedia.com
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Q&A
17Nymble Blocking System
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THANKYOU
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