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: "stegtorrent a steganographic method for the p2p file sharing service"
  Abstract: The paper proposes StegTorrent a new network steganographic method for the popular P2P file transfer service-BitTorrent. It is based on modifying the order of data packets in the peer-peer data exchange protocol. Unlike other existing steganographic methods that modify the packets' order it does not require any synchronization. Experimental results acquired from prototype implementation proved that it provides high steganographic bandwidth of up to 270 b/s while introducing little transmission distortion and providing difficult detectability.

Connected through hyperedge HE-1 (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"
    - "voip steganography and its detection a survey"
    - "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-2 (induced by source paper "steganography in modern smartphones and mitigation techniques"):
  with members:
    - "steganography using the extensible messaging and presence protocol xmpp"
    - "principles and overview of network steganography"
    - "voip steganography and its detection a survey"
    - "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"

Connected through hyperedge HE-3 (induced by source paper "principles and overview of network steganography"):
  with members:
    - "padsteg introducing inter protocol steganography"

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.MM(Multimedia)