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: "active eavesdropping via spoofing relay attack"
  Abstract: This paper studies a new active eavesdropping technique via the so-called spoofing relay attack, which could be launched by the eavesdropper to significantly enhance the information leakage rate from the source over conventional passive eaves-dropping. With this attack, the eavesdropper acts as a relay to spoof the source to vary transmission rate in favor of its eavesdropping performance by either enhancing or degrading the effective channel of the legitimate link. The maxi-mum information leakage rate achievable by the eavesdropper and the corresponding optimal operation at the spoofing relay are obtained. It is shown that such a spoofing relay attack could impose new challenges from a physical-layer security perspective since it leads to significantly higher information leakage rate than conventional passive eavesdropping.

Connected through hyperedge HE-1 (induced by source paper "optimal downlink transmission for cell free swipt massive mimo systems with active eavesdropping"):
  with members:
    - "ubiquitous cell free massive mimo communications"
    - "cell free massive mimo networks optimal power control against active eavesdropping"
    - "spectral and energy efficiency of cell free massive mimo systems with hardware impairments"
    - "on the total energy efficiency of cell free massive mimo"
    - "energy efficiency in cell free massive mimo with zero forcing precoding design"
    - "secrecy and energy efficiency in massive mimo aided heterogeneous c ran a new look at interference"
    - "cell free massive mimo versus small cells"
    - "wireless power transfer in massive mimo aided hetnets with user association"

Connected through hyperedge HE-2 (induced by source paper "wireless information surveillance via proactive eavesdropping with spoofing relay"):
  with members:
    - "proactive eavesdropping via cognitive jamming in fading channels"
    - "proactive eavesdropping via jamming for rate maximization over rayleigh fading channels"
    - "physical layer security for massive mimo an overview on passive eavesdropping and active attacks"
    - "in band full duplex wireless challenges and opportunities"
    - "wireless information and power transfer architecture design and rate energy tradeoff"
    - "a secure communication game with a relay helping the eavesdropper"
    - "mimo broadcasting for simultaneous wireless information and power transfer"
    - "cooperation with an untrusted relay a secrecy perspective"

Connected through hyperedge HE-3 (induced by source paper "transmit optimization for symbol level spoofing"):
  with members:
    - "wireless surveillance of two hop communications"
    - "surveillance and intervention of infrastructure free mobile communications a new wireless security paradigm"
    - "wireless information surveillance via proactive eavesdropping with spoofing relay"
    - "a survey on wireless security technical challenges recent advances and future trends"
    - "directional modulation via symbol level precoding a way to enhance security"
    - "proactive eavesdropping via cognitive jamming in fading channels"
    - "proactive eavesdropping via jamming for rate maximization over rayleigh fading channels"
    - "constructive multiuser interference in symbol level precoding for the miso downlink channel"

Connected through hyperedge HE-4 (induced by source paper "fundamental rate limits of physical layer spoofing"):
  with members:
    - "surveillance and intervention of infrastructure free mobile communications a new wireless security paradigm"
    - "wireless information surveillance via proactive eavesdropping with spoofing relay"
    - "a survey on wireless security technical challenges recent advances and future trends"
    - "transmit optimization for symbol level spoofing"
    - "proactive eavesdropping via cognitive jamming in fading channels"
    - "proactive eavesdropping via jamming for rate maximization over rayleigh fading channels"

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.IT(Information Theory)