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 the design of perceptual mpeg video encryption algorithms"
  Abstract: In this paper, some existing perceptual encryption algorithms of MPEG videos are reviewed and some problems, especially security defects of two recently proposed MPEG-video perceptual encryption schemes, are pointed out. Then, a simpler and more effective design is suggested, which selectively encrypts fixed-length codewords in MPEG-video bit streams under the control of three perceptibility factors. The proposed design is actually an encryption configuration that can work with any stream cipher or block cipher. Compared with the previously-proposed schemes, the new design provides more useful features, such as strict size-preservation, on-the-fly encryption and multiple perceptibility, which make it possible to support more applications with different requirements. In addition, four different measures are suggested to provide better security against known/chosen-plaintext attacks

Connected through hyperedge HE-1 (induced by source paper "on the security of a class of diffusion mechanisms for image encryption"):
  with members:
    - "chosen plaintext attack of an image encryption scheme based on modified permutation diffusion structure"
    - "a chaotic image encryption scheme owning temp value feedback"
    - "local shannon entropy measure with statistical tests for image randomness"
    - "breaking a chaotic image encryption algorithm based on modulo addition and xor operation"
    - "a general quantitative cryptanalysis of permutation only multimedia ciphers against plaintext attacks"
    - "a fast image encryption scheme based on chaotic standard map"

Connected through hyperedge HE-2 (induced by source paper "cryptanalyzing an image encryption algorithm based on scrambling and veginere cipher"):
  with members:
    - "a chaotic image encryption scheme owning temp value feedback"
    - "a general quantitative cryptanalysis of permutation only multimedia ciphers against plaintext attacks"

Connected through hyperedge HE-3 (induced by source paper "recovering missing coefficients in dct transformed images"):
  with members:
    - "an improved dc recovery method from ac coefficients of dct transformed images"

Connected through hyperedge HE-4 (induced by source paper "an improved dc recovery method from ac coefficients of dct transformed images"):
  with members:
    - "a general quantitative cryptanalysis of permutation only multimedia ciphers against plaintext attacks"

Connected through hyperedge HE-5 (induced by source paper "on the security defects of an image encryption scheme"):
  with members:
    - "a general quantitative cryptanalysis of permutation only multimedia ciphers against plaintext attacks"
    - "cryptanalyzing an encryption scheme based on blind source separation"

Connected through hyperedge HE-6 (induced by source paper "cryptanalyzing an encryption scheme based on blind source separation"):
  with members:
    - "a general quantitative cryptanalysis of permutation only multimedia ciphers against plaintext attacks"
    - "security problems with improper implementations of improved fea m"
    - "on the security of the yen guo s domino signal encryption algorithm dsea"

Connected through hyperedge HE-7 (induced by source paper "cryptanalysis of an image encryption scheme based on the hill cipher"):
  with members:
    - "on the security defects of an image encryption scheme"
    - "on the security of the yen guo s domino signal encryption algorithm dsea"
    - "chosen plaintext cryptanalysis of a clipped neural network based chaotic cipher"

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)