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: "classical authentication aided three stage quantum protocol"
  Abstract: This paper modifies Kak's three-stage protocol so that it can guarantee secure transmission of information. Although avoiding man-in-the-middle attack is our primary objective in the introduction of classical authentication inside the three-stage protocol, we also benefit from the inherent advantages of the chosen classical authentication protocol. We have tried to implement ideas like key distribution center, session key, time-stamp, and nonce, within the quantum cryptography protocol.

Connected through hyperedge HE-1 (induced by source paper "comparing bb84 and authentication aided kak s three stage quantum protocol"):
  with members:
    - "trusted certificates in quantum cryptography"
    - "implementing the three stage quantum cryptography protocol"

Connected through hyperedge HE-2 (induced by source paper "variations on kak s three stage quantum cryptography protocol"):
  with members:
    - "trusted certificates in quantum cryptography"

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)