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: "public key cryptography based on semigroup actions"
  Abstract: A generalization of the original Diffie-Hellman key exchange in $(\Z/p\Z)^*$ found a new depth when Miller and Koblitz suggested that such a protocol could be used with the group over an elliptic curve. In this paper, we propose a further vast generalization where abelian semigroups act on finite sets. We define a Diffie-Hellman key exchange in this setting and we illustrate how to build interesting semigroup actions using finite (simple) semirings. The practicality of the proposed extensions rely on the orbit sizes of the semigroup actions and at this point it is an open question how to compute the sizes of these orbits in general and also if there exists a square root attack in general. In Section 2 a concrete practical semigroup action built from simple semirings is presented. It will require further research to analyse this system.

Connected through hyperedge HE-1 (induced by source paper "on the algebraic structure of e_p m and applications to cryptography"):
  with members:
    - "group key management based on semigroup actions"
    - "cryptanalysis of a noncommutative key exchange protocol"

Connected through hyperedge HE-2 (induced by source paper "pre and post quantum diffie hellman from groups actions and isogenies"):
  with members:
    - "a note on the security of csidh"
    - "towards practical key exchange from ordinary isogeny graphs"
    - "mathematics of isogeny based cryptography"
    - "a kilobit hidden snfs discrete logarithm computation"
    - "montgomery curves and their arithmetic"
    - "mu kummer efficient hyperelliptic signatures and key exchange on microcontrollers"
    - "general impossibility of group homomorphic encryption in the quantum world"
    - "an l 1 3 discrete logarithm algorithm for low degree curves"

Connected through hyperedge HE-3 (induced by source paper "towards practical key exchange from ordinary isogeny graphs"):
  with members:
    - "nemo hecke computer algebra and number theory packages for the julia programming language"
    - "mathematics of isogeny based cryptography"
    - "montgomery curves and their arithmetic"
    - "fast algorithms for computing isogenies between elliptic curves"

Connected through hyperedge HE-4 (induced by source paper "an application of group theory in confidential network communications"):
  with members:
    - "an active attack on a distributed group key exchange system"
    - "group key management based on semigroup actions"
    - "an active attack on a multiparty key exchange protocol"

Connected through hyperedge HE-5 (induced by source paper "group key management based on semigroup actions"):
  with members:
    - "cryptanalysis of a noncommutative key exchange protocol"
    - "an active attack on a multiparty key exchange protocol"

Connected through hyperedge HE-6 (induced by source paper "cryptanalysis of a noncommutative key exchange protocol"):
  with members:
    - "a general construction for monoid based knapsack protocols"

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)