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: "on covert acoustical mesh networks in air"
  Abstract: Covert channels can be used to circumvent system and network policies by establishing communications that have not been considered in the design of the computing system. We construct a covert channel between different computing systems that utilizes audio modulation/demodulation to exchange data between the computing systems over the air medium. The underlying network stack is based on a communication system that was originally designed for robust underwater communication. We adapt the communication system to implement covert and stealthy communications by utilizing the ultrasonic frequency range. We further demonstrate how the scenario of covert acoustical communication over the air medium can be extended to multi-hop communications and even to wireless mesh networks. A covert acoustical mesh network can be conceived as a meshed botnet or malnet that is accessible via inaudible audio transmissions. Different applications of covert acoustical mesh networks are presented, including the use for remote keylogging over multiple hops. It is shown that the concept of a covert acoustical mesh network renders many conventional security concepts useless, as acoustical communications are usually not considered. Finally, countermeasures against covert acoustical mesh networks are discussed, including the use of lowpass filtering in computing systems and a host-based intrusion detection system for analyzing audio input and output in order to detect any irregularities.

Connected through hyperedge HE-1 (induced by source paper "your noise my signal exploiting switching noise for stealthy data exfiltration from desktop computers"):
  with members:
    - "high efficiency power side channel attack immunity using noise injection in attenuated signature domain"
    - "no free charge theorem a covert channel via usb charging cable on mobile devices"
    - "state of the art in power line communications from the applications to the medium"
    - "fansmitter acoustic data exfiltration from speakerless air gapped computers"
    - "bitwhisper covert signaling channel between air gapped computers using thermal manipulations"

Connected through hyperedge HE-2 (induced by source paper "brightness leaking sensitive data from air gapped workstations via screen brightness"):
  with members:
    - "ctrl alt led leaking data from air gapped computers via keyboard leds"
    - "data exfiltration via multipurpose rfid cards and countermeasures"
    - "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"
    - "usbee air gap covert channel via electromagnetic emission from usb"
    - "fansmitter acoustic data exfiltration from speakerless air gapped computers"
    - "visisploit an optical covert channel to leak data through an air gap"

Connected through hyperedge HE-3 (induced by source paper "ctrl alt led leaking data from air gapped computers via keyboard leds"):
  with members:
    - "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"
    - "usbee air gap covert channel via electromagnetic emission from usb"
    - "fansmitter acoustic data exfiltration from speakerless air gapped computers"
    - "bitwhisper covert signaling channel between air gapped computers using thermal manipulations"
    - "airhopper bridging the air gap between isolated networks and mobile phones using radio frequencies"

Connected through hyperedge HE-4 (induced by source paper "data exfiltration via multipurpose rfid cards and countermeasures"):
  with members:
    - "optical exfiltration of data via keyboard led status indicators to ip cameras"
    - "spectre attacks exploiting speculative execution"
    - "xled covert data exfiltration from air gapped networks via router leds"
    - "usbee air gap covert channel via electromagnetic emission from usb"
    - "fansmitter acoustic data exfiltration from speakerless air gapped computers"
    - "airhopper bridging the air gap between isolated networks and mobile phones using radio frequencies"

Connected through hyperedge HE-5 (induced by source paper "optical exfiltration of data via keyboard led status indicators to ip cameras"):
  with members:
    - "xled covert data exfiltration from air gapped networks via router leds"
    - "fansmitter acoustic data exfiltration from speakerless air gapped computers"
    - "thermal covert channels on multi core platforms"
    - "airhopper bridging the air gap between isolated networks and mobile phones using radio frequencies"

Connected through hyperedge HE-6 (induced by source paper "powerhammer exfiltrating data from air gapped computers through power lines"):
  with members:
    - "data exfiltration via multipurpose rfid cards and countermeasures"
    - "optical exfiltration of data via keyboard led status indicators to ip cameras"
    - "optical tempest"
    - "odini escaping sensitive data from faraday caged air gapped computers via magnetic fields"
    - "magneto covert channel between air gapped systems and nearby smartphones via cpu generated magnetic fields"
    - "mosquito covert ultrasonic transmissions between two air gapped computers using speaker to speaker communication"
    - "air jumper covert air gap exfiltration infiltration via security cameras infrared ir"
    - "xled covert data exfiltration from air gapped networks via router leds"

Connected through hyperedge HE-7 (induced by source paper "survey and systematization of secure device pairing"):
  with members:
    - "demo of bandana body area network device to device authentication using natural gait"
    - "rapid user transparent and trustworthy device pairing for d2d enabled mobile crowdsourcing"
    - "walk unlock zero interaction authentication protected with multi modal gait biometrics"
    - "challenges in mobile multi device ecosystems"
    - "when theory and reality collide demystifying the effectiveness of ambient sensing for nfc based proximity detection by applying relay attack data"
    - "stash securing transparent authentication schemes using prover side proximity verification"
    - "contextual proximity detection in the face of context manipulating adversaries"
    - "pitfalls in designing zero effort deauthentication opportunistic human observation attacks"

Connected through hyperedge HE-8 (induced by source paper "beatcoin leaking private keys from air gapped cryptocurrency wallets"):
  with members:
    - "spectre attacks exploiting speculative execution"
    - "powerhammer exfiltrating data from air gapped computers through power lines"
    - "odini escaping sensitive data from faraday caged air gapped computers via magnetic fields"
    - "magneto covert channel between air gapped systems and nearby smartphones via cpu generated magnetic fields"
    - "mosquito covert ultrasonic transmissions between two air gapped computers using speaker to speaker communication"
    - "air jumper covert air gap exfiltration infiltration via security cameras infrared ir"
    - "xled covert data exfiltration from air gapped networks via router leds"
    - "usbee air gap covert channel via electromagnetic emission from usb"

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)