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 survey of p2p network security"
  Abstract: This paper presents a review of peer-to-peer network security. Popular for sharing of multimedia files, these networks carry risks and vulnerabilities relating to data integrity, spyware, adware, and unwanted files. Further attacks include those of forgery, pollution, repudiation, membership and Eclipse attacks, neighbor selection attacks, Sybil, DoS, and omission attacks. We review some protection mechanisms that have been devised.

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

Connected through hyperedge HE-2 (induced by source paper "a review of man in the middle attacks"):
  with members:
    - "authentication using piggy bank approach to secure double lock cryptography"
    - "the piggy bank cryptographic trope"
    - "public key infrastructure based on authentication of media attestments"

Connected through hyperedge HE-3 (induced by source paper "coding side information for implementing cubic transformation"):
  with members:
    - "a review of man in the middle attacks"
    - "survey of sybil attacks in social networks"
    - "the piggy bank cryptographic trope"

Connected through hyperedge HE-4 (induced by source paper "survey of sybil attacks in social networks"):
  with members:
    - "a review of man in the middle attacks"
    - "social turing tests crowdsourcing sybil detection"
    - "uncovering social network sybils in the wild"

Connected through hyperedge HE-5 (induced by source paper "new class of pseudorandom d sequences to generate cryptographic keys"):
  with members:
    - "randomness of d sequences via diehard testing"
    - "binary random sequences obtained from decimal sequences"
    - "testing d sequences for their randomness"

Connected through hyperedge HE-6 (induced by source paper "connectivity in social networks"):
  with members:
    - "a review of man in the middle attacks"
    - "survey of sybil attacks in social networks"

Connected through hyperedge HE-7 (induced by source paper "binary gh sequences for multiparty communication"):
  with members:
    - "a review of man in the middle attacks"
    - "a class of random sequences for key generation"

Connected through hyperedge HE-8 (induced by source paper "generating primes using partitions"):
  with members:
    - "the piggy bank cryptographic trope"

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)