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: "designing a blockchain based iot with ethereum swarm and lora the software solution to create high availability with minimal security risks"
  Abstract: Today, the number of Internet of Things (IoT) devices in all aspects of life is increasing exponentially. Our cities are getting smarter and informing us about our surroundings in a contextual manner. However, we face significant challenges in deploying, managing, and collecting data from these devices. In addition, we must address the problem of storing and mining that data for higher-quality IoT services. Blockchain technology, even in today's nascent form, has the potential to be the foundation for a common, distributed, trustless, and autonomous infrastructure system. This article describes a standardized IoT infrastructure where data are stored on a distributed storage service that is fault-tolerant and resistant to distributed denial of service (DDOS) attacks and data access is managed by a decentralized, trustless blockchain. The illustrated system used LoRa as the emerging network technology, Swarm as the distributed data storage platform, and Ethereum as the blockchain platform. Such a data back end will ensure high availability with minimal security risks while replacing traditional back-end systems with a single "smart contract."

Connected through hyperedge HE-1 (induced by source paper "integration of blockchain and cloud of things architecture applications and challenges"):
  with members:
    - "ekiden a platform for confidentiality preserving trustworthy and performant smart contracts"
    - "blockchain technologies for the internet of things research issues and challenges"
    - "a survey on consensus mechanisms and mining strategy management in blockchain networks"
    - "energy crowdsourcing and peer to peer energy trading in blockchain enabled smart grids"
    - "bpds a blockchain based privacy preserving data sharing for electronic medical records"
    - "a survey on the security of blockchain systems"
    - "wip a novel blockchain based trust model for cloud identity management"
    - "blockchain based smart contracts applications and challenges"

Connected through hyperedge HE-2 (induced by source paper "pufchain hardware assisted blockchain for sustainable simultaneous device and data security in the internet of everything ioe"):
  with members:
    - "secured by blockchain safeguarding internet of things devices"
    - "blendcac a blockchain enabled decentralized capability based access control for iots"
    - "edgechain an edge iot framework and prototype based on blockchain and smart contracts"
    - "a survey on security and privacy issues of bitcoin"
    - "a review on internet of things iot internet of everything ioe and internet of nano things iont"

Connected through hyperedge HE-3 (induced by source paper "biometric template storage with blockchain a first look into cost and performance tradeoffs"):
  with members:
    - "blockchain and biometrics a first look into opportunities and challenges"
    - "ipfs content addressed versioned p2p file system"

Connected through hyperedge HE-4 (induced by source paper "idmob iot data marketplace on blockchain"):
  with members:
    - "blockbench a framework for analyzing private blockchains"
    - "ipfs content addressed versioned p2p file system"

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)