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: "montgomery curves and their arithmetic"
  Abstract: Three decades ago, Montgomery introduced a new elliptic curve model for use in Lenstra's ECM factorization algorithm. Since then, his curves and the algorithms associated with them have become foundational in the implementation of elliptic curve cryptosystems. This article surveys the theory and cryptographic applications of Montgomery curves over non-binary finite fields, including Montgomery's x-only arithmetic and Ladder algorithm, x-only Diffie--Hellman, y-coordinate recovery, and 2-dimensional and Euclidean differential addition chains such as Montgomery's PRAC algorithm.

Connected through hyperedge HE-1 (induced by source paper "stronger and faster side channel protections for csidh"):
  with members:
    - "towards practical key exchange from ordinary isogeny graphs"

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"
    - "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"
    - "public key cryptography based on semigroup actions"

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"
    - "fast algorithms for computing isogenies between elliptic curves"
    - "public key cryptography based on semigroup actions"

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)