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: "voip steganography and its detection a survey"
  Abstract: Steganography is an ancient art that encompasses various techniques of information hiding, the aim of which is to secret information into a carrier message. Steganographic methods are usually aimed at hiding the very existence of the communication. Due to the rise in popularity of IP telephony, together with the large volume of data and variety of protocols involved, it is currently attracting the attention of the research community as a perfect carrier for steganographic purposes. This paper is a survey of the existing VoIP steganography (steganophony) methods and their countermeasures.

Connected through hyperedge HE-1 (induced by source paper "hierarchical representation network for steganalysis of qim steganography in low bit rate speech signals"):
  with members:
    - "fcem a novel fast correlation extract model for real time steganalysis of voip stream via multi head attention"
    - "real time steganalysis for stream media based on multi channel convolutional sliding windows"
    - "bert pre training of deep bidirectional transformers for language understanding"
    - "attention is all you need"
    - "deep residual learning for image recognition"
    - "batch normalization accelerating deep network training by reducing internal covariate shift"
    - "adam a method for stochastic optimization"
    - "convolutional neural networks for sentence classification"

Connected through hyperedge HE-2 (induced by source paper "the new threats of information hiding the road ahead"):
  with members:
    - "information hiding as a challenge for malware detection"
    - "stealthy malware traffic not as innocent as it looks"

Connected through hyperedge HE-3 (induced by source paper "youskyde information hiding for skype video traffic"):
  with members:
    - "hidden and uncontrolled on the emergence of network steganographic threats"
    - "on steganography in lost audio packets"
    - "lack a voip steganographic method"

Connected through hyperedge HE-4 (induced by source paper "hidden and uncontrolled on the emergence of network steganographic threats"):
  with members:
    - "a pattern based survey and categorization of network covert channel techniques"
    - "steganography in modern smartphones and mitigation techniques"
    - "stegtorrent a steganographic method for the p2p file sharing service"
    - "padsteg introducing inter protocol steganography"
    - "sending hidden data via google suggest"
    - "using transcoding for hidden communication in ip telephony"
    - "how hidden can be even more hidden"
    - "steganographic routing in multi agent system environment"

Connected through hyperedge HE-5 (induced by source paper "steganography in modern smartphones and mitigation techniques"):
  with members:
    - "steganography using the extensible messaging and presence protocol xmpp"
    - "stegtorrent a steganographic method for the p2p file sharing service"
    - "principles and overview of network steganography"
    - "using transcoding for hidden communication in ip telephony"
    - "lost audio packets steganography the first practical evaluation"
    - "capacity of steganographic channels"
    - "lack a voip steganographic method"

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)