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: "the cubic public key transformation"
  Abstract: We propose the use of the cubic transformation for public-key applications and digital signatures. Transformations modulo a prime p or a composite n=pq, where p and q are primes, are used in such a fashion that each transformed value has only 3 roots that makes it a more efficient transformation than the squaring transformation of Rabin, which has 4 roots. Such a transformation, together with additional tag information, makes it possible to uniquely invert each transformed value. The method may be used for other exponents as well.

Connected through hyperedge HE-1 (induced by source paper "generating target probability sequences and events"):
  with members:
    - "the piggy bank cryptographic trope"
    - "oblivious transfer based on key exchange"

Connected through hyperedge HE-2 (induced by source paper "indexing properties of primitive pythagorean triples for cryptography applications"):
  with members:
    - "pythagorean triples and cryptographic coding"

Connected through hyperedge HE-3 (induced by source paper "a distributed data storage scheme for sensor networks"):
  with members:
    - "internet voting protocol based on implicit data security"

Connected through hyperedge HE-4 (induced by source paper "binary random sequences obtained from decimal sequences"):
  with members:
    - "testing kak s conjecture on binary reciprocal of primes and cryptographic applications"
    - "testing d sequences for their randomness"
    - "period of the d sequence based random number generator"
    - "a d sequence based recursive random number generator"
    - "watermarking using decimal sequences"

Connected through hyperedge HE-5 (induced by source paper "period of the d sequence based random number generator"):
  with members:
    - "testing d sequences for their randomness"
    - "a d sequence based recursive random number generator"
    - "watermarking using decimal sequences"

Connected through hyperedge HE-6 (induced by source paper "a quasigroup based cryptographic system"):
  with members:
    - "candidate one way functions and one way permutations based on quasigroup string transformations"
    - "stream cipher based on quasigroup string transformations in z p"

Connected through hyperedge HE-7 (induced by source paper "improved watermarking scheme using decimal sequences"):
  with members:
    - "a d sequence based recursive random number generator"
    - "watermarking using decimal sequences"

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)