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: "interacting with the internet of things using smart contracts and blockchain technologies"
  Abstract: Despite technological advances, most smart objects in the Internet of Things (IoT) cannot be accessed using technologies designed and developed for interacting with powerful Internet servers. IoT use cases involve devices that not only have limited resources, but also they are not always connected to the Internet and are physically exposed to tampering. In this paper, we describe the design, development, and evaluation of a smart contract-based solution that allows end-users to securely interact with smart devices. Our approach enables access control, Thing authentication, and payments in a fully decentralized setting, taking at the same time into consideration the limitations and constraints imposed by both blockchain technologies and the IoT paradigm. Our prototype implementation is based on existing technologies, i.e., Ethereum smart contracts, which makes it realistic and fundamentally secure.

Connected through hyperedge HE-1 (induced by source paper "oauth 2 0 authorization using blockchain based tokens"):
  with members:
    - "oauth 2 0 meets blockchain for authorization in constrained iot environments"
    - "smart contract based access control for the internet of things"

Connected through hyperedge HE-2 (induced by source paper "towards blockchain based multi agent robotic systems analysis classification and applications"):
  with members:
    - "a reference architecture for smart and software defined buildings"
    - "controlling robots using artificial intelligence and a consortium blockchain"
    - "blockchain solutions for multi agent robotic systems related work and open questions"
    - "towards the internet of robotic things analysis architecture components and challenges"
    - "robochain a secure data sharing framework for human robot interaction"
    - "an architecture for distributed ledger based m2m auditing for electric autonomous vehicles"
    - "smart contracts for multiagent plan execution in untrusted cyber physical systems"
    - "towards blockchain based robonomics autonomous agents behavior validation"

Connected through hyperedge HE-3 (induced by source paper "interledger smart contracts for decentralized authorization to constrained things"):
  with members:
    - "blendcac a blockchain enabled decentralized capability based access control for iots"
    - "smart contract based access control for the internet of things"

Connected through hyperedge HE-4 (induced by source paper "oauth 2 0 meets blockchain for authorization in constrained iot environments"):
  with members:
    - "blendcac a blockchain enabled decentralized capability based access control for iots"
    - "smart contract based access control for the internet of things"

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)