Security and Privacy in Communication Networks. 7th International ICST Conference, SecureComm 2011, London, UK, September 7-9, 2011, Revised Selected Papers

Research Article

Analyzing the Gold Star Scheme in a Split Tor Network

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  • @INPROCEEDINGS{10.1007/978-3-642-31909-9_5,
        author={Benedikt Westermann and Pern Chia and Dogan Kesdogan},
        title={Analyzing the Gold Star Scheme in a Split Tor Network},
        proceedings={Security and Privacy in Communication Networks. 7th International ICST Conference, SecureComm 2011, London, UK, September 7-9, 2011, Revised Selected Papers},
        proceedings_a={SECURECOMM},
        year={2012},
        month={10},
        keywords={Tor Incentive Schemes Gold Star Split Network},
        doi={10.1007/978-3-642-31909-9_5}
    }
    
  • Benedikt Westermann
    Pern Chia
    Dogan Kesdogan
    Year: 2012
    Analyzing the Gold Star Scheme in a Split Tor Network
    SECURECOMM
    Springer
    DOI: 10.1007/978-3-642-31909-9_5
Benedikt Westermann1,*, Pern Chia1,*, Dogan Kesdogan,*
  • 1: Q2S, NTNU
*Contact email: westermann@q2s.ntnu.no, chia@q2s.ntnu.no, kesdogan@q2s.ntnu.no

Abstract

Tor is an anonymity network and two challenges in Tor are (i) to overcome the scalability problems of Tor’s current network information distribution scheme, and (ii) to motivate users to become operators of nodes. Several solutions have been proposed to address these challenges. We investigate the ramifications of combining two seemingly promising proposals, i.e., splitting the Tor network into several sub-networks (for better scalability), while using the Gold Star scheme (for motivating users to become node operators). Through simulation, we show that the sub-networks are likely to end up in a state of highly imbalanced division of size and bandwidth. This threatens the security and worsens the scalability problem of Tor. We identify the ratio of nodes given a gold star and the fact that a gold star is solely awarded based on a node’s bandwidth, being highly skewed in practice, as two factors that contribute to an imbalanced split. We explore several potential mitigating strategies and discuss their strengths and shortcomings.