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 review of man in the middle attacks"
  Abstract: This paper presents a survey of man-in-the-middle (MIM) attacks in communication networks and methods of protection against them. In real time communication, the attack can in many situations be discovered by the use of timing information. The most common attacks occur due to Address Resolution Protocol (ARP) cache poisoning, DNS spoofing, session hijacking, and SSL hijacking.

Connected through hyperedge HE-1 (induced by source paper "multiparty probability computation and verification"):
  with members:
    - "oblivious transfer protocol with verification"
    - "generating primes using partitions"
    - "a survey of p2p network security"
    - "survey of sybil attacks in social networks"
    - "the piggy bank cryptographic trope"

Connected through hyperedge HE-2 (induced by source paper "coding side information for implementing cubic transformation"):
  with members:
    - "a survey of p2p network security"
    - "survey of sybil attacks in social networks"
    - "the piggy bank cryptographic trope"

Connected through hyperedge HE-3 (induced by source paper "survey of sybil attacks in social networks"):
  with members:
    - "a survey of p2p network security"
    - "social turing tests crowdsourcing sybil detection"
    - "uncovering social network sybils in the wild"

Connected through hyperedge HE-4 (induced by source paper "connectivity in social networks"):
  with members:
    - "a survey of p2p network security"
    - "survey of sybil attacks in social networks"

Connected through hyperedge HE-5 (induced by source paper "binary gh sequences for multiparty communication"):
  with members:
    - "a class of random sequences for key generation"
    - "a survey of p2p network security"

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)