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: "speake a r turn speakers to microphones for fun and profit"
  Abstract: It is possible to manipulate the headphones (or earphones) connected to a computer, silently turning them into a pair of eavesdropping microphones - with software alone. The same is also true for some types of loudspeakers. This paper focuses on this threat in a cyber-security context. We present SPEAKE(a)R, a software that can covertly turn the headphones connected to a PC into a microphone. We present technical background and explain why most of PCs and laptops are susceptible to this type of attack. We examine an attack scenario in which malware can use a computer as an eavesdropping device, even when a microphone is not present, muted, taped, or turned off. We measure the signal quality and the effective distance, and survey the defensive countermeasures.

Connected through hyperedge HE-1 (induced by source paper "taxonomy and challenges of out of band signal injection attacks and defenses"):
  with members:
    - "understanding the effectiveness of ultrasonic microphone jammer"
    - "a framework for evaluating security in the presence of signal injection attacks"
    - "trick or heat manipulating critical temperature based control systems using rectification attacks"
    - "spearphone a speech privacy exploit via accelerometer sensed reverberations from smartphone loudspeakers"
    - "oops had the silly thing in reverse optical injection attacks in through led status indicators"
    - "signal jamming attacks against communication based train control attack impact and countermeasure"
    - "systematic classification of side channel attacks a case study for mobile devices"
    - "injected and delivered fabricating implicit control over actuation systems by spoofing inertial sensors"

Connected through hyperedge HE-2 (induced by source paper "oops had the silly thing in reverse optical injection attacks in through led status indicators"):
  with members:
    - "synesthesia detecting screen content via remote acoustic side channels"
    - "optical tempest"
    - "powerhammer exfiltrating data from air gapped computers through power lines"
    - "magneto covert channel between air gapped systems and nearby smartphones via cpu generated magnetic fields"
    - "beatcoin leaking private keys from air gapped cryptocurrency wallets"
    - "oops i think i scanned a malware"
    - "air jumper covert air gap exfiltration infiltration via security cameras infrared ir"
    - "xled covert data exfiltration from air gapped networks via router leds"

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)