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: "a new chaos based watermarking algorithm"
  Abstract: This paper introduces a new watermarking algorithm based on discrete chaotic iterations. After defining some coefficients deduced from the description of the carrier medium, chaotic discrete iterations are used to mix the watermark and to embed it in the carrier medium. It can be proved that this procedure generates topological chaos, which ensures that desired properties of a watermarking algorithm are satisfied.

Connected through hyperedge HE-1 (induced by source paper "an optimization technique on pseudorandom generators based on chaotic iterations"):
  with members:
    - "class of trustworthy pseudo random number generators"
    - "topological chaos and chaotic iterations application to hash functions"
    - "improving random number generators by chaotic iterations application in data hiding"
    - "a pseudo random numbers generator based on chaotic iterations application to watermarking"

Connected through hyperedge HE-2 (induced by source paper "a cryptographic approach for steganography"):
  with members:
    - "lyapunov exponent evaluation of a digital watermarking scheme proven to be secure"
    - "steganography a class of algorithms having secure properties"
    - "chaotic iterations versus spread spectrum chaos and stego security"

Connected through hyperedge HE-3 (induced by source paper "an improved watermarking scheme for internet applications"):
  with members:
    - "topological chaos and chaotic iterations application to hash functions"

Connected through hyperedge HE-4 (induced by source paper "fpga design for pseudorandom number generator based on chaotic iteration used in information hiding application"):
  with members:
    - "hash functions using chaotic iterations"
    - "an optimization technique on pseudorandom generators based on chaotic iterations"
    - "steganography a class of secure and robust algorithms"
    - "evaluating quality of chaotic pseudo random generators application to information hiding"
    - "topological chaos and chaotic iterations application to hash functions"
    - "chaotic iterations versus spread spectrum chaos and stego security"

Connected through hyperedge HE-5 (induced by source paper "neural networks and chaos construction evaluation of chaotic networks and prediction of chaos with multilayer feedforward networks"):
  with members:
    - "hash functions using chaotic iterations"
    - "chaotic iterations versus spread spectrum chaos and stego security"

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)