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: "a secure key agreement protocol for dynamic group"
  Abstract: To accomplish secure group communication, it is essential to share a unique cryptographic key among group members. The underlying challenges to group key agreement are scalability, efficiency, and security. In a dynamic group environment, the rekeying process is more frequent; therefore, it is more crucial to design an efficient group key agreement protocol. Moreover, with the emergence of various group-based services, it is becoming common for several multicast groups to coexist in the same network. These multicast groups may have several shared users; a join or leave request by a single user can trigger regeneration of multiple group keys. Under the given circumstances the rekeying process becomes a challenging task. In this work, we propose a novel methodology for group key agreement which exploits the state vectors of group members. The state vector is a set of randomly generated nonce instances which determine the logical link between group members and which empowers the group member to generate multiple cryptographic keys independently. Using local knowledge of a secret nonce, each member can generate and share a large number of secure keys, indicating that SGRS inherently provides a considerable amount of secure subgroup multicast communication using subgroup multicasting keys derived from local state vectors. The resulting protocol is secure and efficient in terms of both communication and computation.

Connected through hyperedge HE-1 (induced by source paper "secure distribution of protected content in information centric networking"):
  with members:
    - "network coding approach for information centric networking"
    - "a cache management scheme for efficient content eviction and replication in cache networks"
    - "time assisted authentication protocol"

Connected through hyperedge HE-2 (induced by source paper "an authentication protocol for future sensor networks"):
  with members:
    - "a cache management scheme for efficient content eviction and replication in cache networks"
    - "time assisted authentication protocol"
    - "time aware least recent used tlru cache management policy in icn"

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)