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: "droplet decentralized authorization for iot data streams"
  Abstract: This paper presents Droplet, a decentralized data access control service, which operates without intermediate trust entities. Droplet enables data owners to securely and selectively share their dat ...

Connected through hyperedge HE-1 (induced by source paper "jedi many to many end to end encryption and key delegation for iot"):
  with members:
    - "nucypher kms decentralized key management system"
    - "distributed authorization in vanadium"
    - "privacy discovery and authentication for the internet of things"
    - "riposte an anonymous messaging system handling millions of users"
    - "cryptographic enforcement of information flow policies without public information"

Connected through hyperedge HE-2 (induced by source paper "timecrypt a scalable private time series data store"):
  with members:
    - "prio private robust and scalable computation of aggregate statistics"
    - "macrobase prioritizing attention in fast data"

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)