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: "a distributed protocol for detection of packet dropping attack in mobile ad hoc networks"
  Abstract: In multi-hop mobile ad hoc networks (MANETs),mobile nodes cooperate with each other without using any infrastructure such as access points or base stations. Security remains a major challenge for these networks due to their features of open medium, dynamically changing topologies, reliance on cooperative algorithms, absence of centralized monitoring points, and lack of clear lines of defense. Among the various attacks to which MANETs are vulnerable, malicious packet dropping attack is very common where a malicious node can partially degrade or completely disrupt communication in the network by consistently dropping packets. In this paper, a mechanism for detection of packet dropping attack is presented based on cooperative participation of the nodes in a MANET. The redundancy of routing information in an ad hoc network is utilized to make the scheme robust so that it works effectively even in presence of transient network partitioning and Byzantine failure of nodes. The proposed scheme is fully cooperative and thus more secure as the vulnerabilities of any election algorithm used for choosing a subset of nodes for cooperation are absent. Simulation results show the effectiveness of the protocol.

Connected through hyperedge HE-1 (induced by source paper "homomorphic encryption theory and application"):
  with members:
    - "security in wireless sensor networks"
    - "security and privacy issues in wireless mesh networks a survey"
    - "an attack on privacy preserving data aggregation protocol for wireless sensor networks"
    - "secure and privacy preserving data aggregation protocols for wireless sensor networks"
    - "secure and privacy preserving authentication protocols for wireless mesh networks"
    - "a novel mechanism for detection of distributed denial of service attacks"
    - "a mechanism for detection of gray hole attack in mobile ad hoc networks"
    - "reputation and trust based systems for wireless self organizing networks"

Connected through hyperedge HE-2 (induced by source paper "security and privacy issues in wireless mesh networks a survey"):
  with members:
    - "secure and privacy preserving authentication protocols for wireless mesh networks"
    - "reputation and trust based systems for wireless self organizing networks"
    - "secure and privacy aware searching in peer to peer networks"
    - "an efficient and user privacy preserving routing protocol for wireless mesh networks"
    - "cross layer protocols for multimedia communications over wireless networks"
    - "secure routing in wireless mesh networks"
    - "a survey on wireless sensor network security"
    - "a distributed trust management framework for detecting malicious packet dropping nodes in a mobile ad hoc network"

Connected through hyperedge HE-3 (induced by source paper "security in wireless sensor networks"):
  with members:
    - "a mechanism for detection of gray hole attack in mobile ad hoc networks"
    - "secure and privacy aware searching in peer to peer networks"
    - "an efficient and user privacy preserving routing protocol for wireless mesh networks"
    - "a robust and secure aggregation protocol for wireless sensor networks"
    - "a distributed trust management framework for detecting malicious packet dropping nodes in a mobile ad hoc network"
    - "a distributed trust and reputation framework for mobile ad hoc networks"
    - "medians and beyond new aggregation techniques for sensor networks"

Connected through hyperedge HE-4 (induced by source paper "security and privacy challenges in cognitive wireless sensor networks"):
  with members:
    - "secure and privacy aware searching in peer to peer networks"
    - "an efficient and user privacy preserving routing protocol for wireless mesh networks"
    - "a survey on wireless sensor network security"
    - "routing security issues in wireless sensor networks attacks and defenses"

Connected through hyperedge HE-5 (induced by source paper "detection of cooperative black hole attack in wireless ad hoc networks"):
  with members:
    - "a mechanism for detection of cooperative black hole attack in mobile ad hoc networks"

Connected through hyperedge HE-6 (induced by source paper "secure and energy efficient data aggregation in wireless sensor networks"):
  with members:
    - "reputation and trust based systems for wireless self organizing networks"
    - "a robust and secure aggregation protocol for wireless sensor networks"
    - "a trust based detection algorithm of selfish packet dropping nodes in a peer to peer wireless mesh network"
    - "a survey on wireless sensor network security"
    - "a distributed trust and reputation framework for mobile ad hoc networks"

Connected through hyperedge HE-7 (induced by source paper "a mechanism for detection of cooperative black hole attack in mobile ad hoc networks"):
  with members:
    - "observation based cooperation enforcement in ad hoc networks"

Connected through hyperedge HE-8 (induced by source paper "routing security issues in wireless sensor networks attacks and defenses"):
  with members:
    - "medians and beyond new aggregation techniques for sensor 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)