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: "resource requirements and speed versus geometry of unconditionally secure physical key exchanges"
  Abstract: The imperative need for unconditional secure key exchange is expounded by the increasing connectivity of networks and by the increasing number and level of sophistication of cyberattacks. Two concepts that are theoretically information-secure are quantum key distribution (QKD) and Kirchoff-Law-Johnson-Noise (KLJN). However, these concepts require a dedicated connection between hosts in peer-to-peer (P2P) networks which can be impractical and or cost prohibitive. A practical and cost effective method is to have each host share their respective cable(s) with other hosts such that two remote hosts can realize a secure key exchange without the need of an additional cable or key exchanger. In this article we analyze the cost complexities of cable, key exchangers, and time required in the star network. We mentioned the reliability of the star network and compare it with other network geometries. We also conceived a protocol and equation for the number of secure bit exchange periods needed in a star network. We then outline other network geometries and trade-off possibilities that seem interesting to explore.

Connected through hyperedge HE-1 (induced by source paper "current injection attack against the kljn secure key exchange"):
  with members:
    - "random resistor random temperature kirchhoff law johnson noise rrrt kljn key exchange"
    - "comments on a new transient attack on the kish key distribution system"
    - "key exchange trust evaluation in peer to peer sensor networks with unconditionally secure key exchange"
    - "analysis of an attenuator artifact in an experimental attack by gunn allison abbott against the kirchhoff law johnson noise kljn secure key exchange system"
    - "on kljn based secure key distribution in vehicular communication networks"
    - "generalized kirchhoff law johnson noise kljn secure key exchange system using arbitrary resistors"
    - "cable capacitance attack against the kljn secure key exchange"
    - "enhanced usage of keys obtained by physical unconditionally secure distributions"

Connected through hyperedge HE-2 (induced by source paper "cable capacitance attack against the kljn secure key exchange"):
  with members:
    - "random resistor random temperature kirchhoff law johnson noise rrrt kljn key exchange"
    - "analysis of an attenuator artifact in an experimental attack by gunn allison abbott against the kirchhoff law johnson noise kljn secure key exchange system"
    - "generalized kirchhoff law johnson noise kljn secure key exchange system using arbitrary resistors"
    - "current and voltage based bit errors and their combined mitigation for the kirchhoff law johnson noise secure key exchange"
    - "on the security of the kirchhoff law johnson noise kljn communicator"
    - "securing vehicle communication systems by the kljn key exchange protocol"
    - "on the cracking scheme in the paper a directional coupler attack against the kish key distribution system by gunn allison and abbott"
    - "elimination of a second law attack and all cable resistance based attacks in the kirchhoff law johnson noise kljn secure key exchange system"

Connected through hyperedge HE-3 (induced by source paper "key exchange trust evaluation in peer to peer sensor networks with unconditionally secure key exchange"):
  with members:
    - "analysis of an attenuator artifact in an experimental attack by gunn allison abbott against the kirchhoff law johnson noise kljn secure key exchange system"
    - "on kljn based secure key distribution in vehicular communication networks"
    - "enhanced usage of keys obtained by physical unconditionally secure distributions"
    - "what kind of noise guarantees security for the kirchhoff law johnson noise key exchange"
    - "on the security of the kirchhoff law johnson noise kljn communicator"
    - "securing vehicle communication systems by the kljn key exchange protocol"
    - "noise properties in the ideal kirchhoff law johnson noise secure communication system"
    - "on the cracking scheme in the paper a directional coupler attack against the kish key distribution system by gunn allison and abbott"

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)