human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "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.

Includes members:
  Member "influence of speech codecs selection on transcoding steganography":
    also connected through other hyperedges:
      (none)
  Member "steganalysis of transcoding steganography":
    also connected through other hyperedges:
      (none)
  Member "using transcoding for hidden communication in ip telephony":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "movesteg a method of network steganography detection")
  Member "lost audio packets steganography the first practical evaluation":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "fundamental limits of covert packet insertion")
  Member "what are suspicious voip delays":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "lost audio packets steganography the first practical evaluation")
  Member "steganography of voip streams":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "trends toward real time network data steganography")
  Member "lack a voip steganographic method":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "youskyde information hiding for skype video traffic")
  Member "covert channels in sip for voip signalling":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "fundamental limits of covert packet insertion")

Question: Please tell me which class the source paper 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)