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: "distributed authorization in vanadium"
  Abstract: In this tutorial, we present an authorization model for distributed systems that operate with limited internet connectivity. Reliable internet access remains a luxury for a majority of the world's population. Even for those who can afford it, a dependence on internet connectivity may lead to sub-optimal user experiences. With a focus on decentralized deployment, we present an authorization model that is suitable for scenarios where devices right next to each other (such as a sensor or a friend's phone) should be able to communicate securely in a peer-to-peer manner. The model has been deployed as part of an open-source distributed application framework called Vanadium. As part of this tutorial, we survey some of the key ideas and techniques used in distributed authorization, and explain how they are combined in the design of our model.

Connected through hyperedge HE-1 (induced by source paper "jedi many to many end to end encryption and key delegation for iot"):
  with members:
    - "droplet decentralized authorization for iot data streams"
    - "nucypher kms decentralized key management system"
    - "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 "droplet decentralized authorization for iot data streams"):
  with members:
    - "timecrypt a scalable private time series data store"
    - "towards blockchain based auditable storage and sharing of iot data"
    - "consensus in the age of blockchains"
    - "casper the friendly finality gadget"
    - "hijacking bitcoin routing attacks on cryptocurrencies"
    - "enhancing bitcoin security and performance with strong consistency via collective signing"
    - "bitcoin ng a scalable blockchain protocol"
    - "majority is not enough bitcoin mining is vulnerable"

Connected through hyperedge HE-3 (induced by source paper "hcap a history based capability system for iot devices"):
  with members:
    - "on the parameterized complexity and kernelization of the workflow satisfiability problem"

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)