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: "watermarking using decimal sequences"
  Abstract: This paper introduces the use of decimal sequences in a code division multiple access (CDMA) based watermarking system to hide information for authentication in black and white images. Matlab version 6.5 was used to implement the algorithms discussed in this paper. The advantage of using d-sequences over PN sequences is that one can choose from a variety of prime numbers which provides a more flexible system.

Connected through hyperedge HE-1 (induced by source paper "a class of random sequences for key generation"):
  with members:
    - "binary random sequences obtained from decimal sequences"
    - "variations on the fibonacci universal code"

Connected through hyperedge HE-2 (induced by source paper "survey of key distribution schemes for wireless sensor networks"):
  with members:
    - "random residue sequences and the number theoretic hilbert transform"
    - "a key set cipher for wireless sensor networks"
    - "the piggy bank cryptographic trope"
    - "randomness of d sequences via diehard testing"

Connected through hyperedge HE-3 (induced by source paper "a wireless system using random residue sequences"):
  with members:
    - "random residue sequences and the number theoretic hilbert transform"
    - "a key set cipher for wireless sensor networks"
    - "randomness of d sequences via diehard testing"
    - "the number theoretic hilbert transform"

Connected through hyperedge HE-4 (induced by source paper "efficient key generation for dynamic blom s scheme"):
  with members:
    - "key management in wireless sensor networks using a modified blom scheme"
    - "testing d sequences for their randomness"

Connected through hyperedge HE-5 (induced by source paper "random residue sequences and the number theoretic hilbert transform"):
  with members:
    - "new results on the number theoretic hilbert transform"
    - "the 10 point and 12 point number theoretic hilbert transform"
    - "the number theoretic hilbert transform"
    - "the basic discrete hilbert transform with an information hiding application"

Connected through hyperedge HE-6 (induced by source paper "two dimensional random patterns"):
  with members:
    - "the algebra of two dimensional patterns"
    - "unary coding for neural network learning"

Connected through hyperedge HE-7 (induced by source paper "cryptographic hardening of d sequences"):
  with members:
    - "new results on scrambling using the mesh array"
    - "on the mesh array for matrix multiplication"

Connected through hyperedge HE-8 (induced by source paper "visual secret sharing scheme using grayscale images"):
  with members:
    - "a recursive threshold visual cryptography scheme"

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)