human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "pisces anonymous communication using social networks"
  Abstract: The architectures of deployed anonymity systems such as Tor suffer from two key problems that limit user's trust in these systems. First, paths for anonymous communication are built without considering trust relationships between users and relays in the system. Second, the network architecture relies on a set of centralized servers. In this paper, we propose Pisces, a decentralized protocol for anonymous communications that leverages users' social links to build circuits for onion routing. We argue that such an approach greatly improves the system's resilience to attackers. #R##N#A fundamental challenge in this setting is the design of a secure process to discover peers for use in a user's circuit. All existing solutions for secure peer discovery leverage structured topologies and cannot be applied to unstructured social network topologies. In Pisces, we discover peers by using random walks in the social network graph with a bias away from highly connected nodes to prevent a few nodes from dominating the circuit creation process. To secure the random walks, we leverage the reciprocal neighbor policy: if malicious nodes try to exclude honest nodes during peer discovery so as to improve the chance of being selected, then honest nodes can use a tit-for-tat approach and reciprocally exclude the malicious nodes from their routing tables. We describe a fully decentralized protocol for enforcing this policy, and use it to build the Pisces anonymity system. #R##N#Using theoretical modeling and experiments on real-world social network topologies, we show that (a) the reciprocal neighbor policy mitigates active attacks that an adversary can perform, (b) our decentralized protocol to enforce this policy is secure and has low overhead, and (c) the overall anonymity provided by our system significantly outperforms existing approaches.

Connected through hyperedge HE-1 (induced by source paper "dandelion lightweight cryptocurrency networking with formal anonymity guarantees"):
  with members:
    - "dandelion redesigning the bitcoin network for anonymity"
    - "anonymity properties of the bitcoin p2p network"
    - "hijacking bitcoin routing attacks on cryptocurrencies"
    - "hijacking bitcoin large scale network attacks on cryptocurrencies"
    - "deanonymisation of clients in bitcoin p2p network"
    - "bitcoin over tor isn t a good idea"
    - "spy vs spy rumor source obfuscation"
    - "a robust information source estimator with sparse observations"

Connected through hyperedge HE-2 (induced by source paper "quantification of de anonymization risks in social networks"):
  with members:
    - "an automated social graph de anonymization technique"
    - "preserving link privacy in social network based systems"
    - "de anonymizing social networks"

Connected through hyperedge HE-3 (induced by source paper "linkmirage how to anonymize links in dynamic social systems"):
  with members:
    - "privacy games optimal user centric data obfuscation"
    - "evolution of social attribute networks measurements modeling and implications using google"
    - "preserving link privacy in social network based systems"
    - "de anonymizing social networks"
    - "anonymity in the wild mixes on unstructured networks"

Connected through hyperedge HE-4 (induced by source paper "avoiding the man on the wire improving tor s security with trust aware path selection"):
  with members:
    - "measuring and mitigating as level adversaries against tor"
    - "defending tor from network adversaries a case study of network path prediction"
    - "stealthy traffic analysis of low latency anonymous communication using throughput fingerprinting"

Connected through hyperedge HE-5 (induced by source paper "how far removed are you scalable privacy preserving estimation of social path length with social pal"):
  with members:
    - "conxsense automated context classification for context aware access control"
    - "peershare a system secure distribution of sensitive data among social contacts"
    - "bootstrapping trust in online dating social verification of online dating profiles"
    - "the anatomy of the facebook social graph"
    - "four degrees of separation"

Connected through hyperedge HE-6 (induced by source paper "preserving link privacy in social network based systems"):
  with members:
    - "x vine secure and pseudonymous routing using social networks"
    - "de anonymizing social networks"
    - "anonymity in the wild mixes on unstructured networks"

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.CR(Cryptography and Security)