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: "blockchain technologies for the internet of things research issues and challenges"
  Abstract: This paper presents a comprehensive survey of the existing blockchain protocols for the Internet of Things (IoT) networks. We start by describing the blockchains and summarizing the existing surveys that deal with blockchain technologies. Then, we provide an overview of the application domains of blockchain technologies in IoT, e.g., Internet of Vehicles, Internet of Energy, Internet of Cloud, Edge computing, etc. Moreover, we provide a classification of threat models, which are considered by blockchain protocols in IoT networks, into five main categories, namely identity-based attacks, manipulation-based attacks, cryptanalytic attacks, reputation-based attacks, and service-based attacks. In addition, we provide a taxonomy and a side-by-side comparison of the state-of-the-art methods toward secure and privacy-preserving blockchain technologies with respect to the blockchain model, specific security goals, performance, limitations, computation complexity, and communication overhead. Based on the current survey, we highlight open research challenges and discuss possible future research directions in the blockchain technologies for IoT.

Connected through hyperedge HE-1 (induced by source paper "the security reference architecture for blockchains towards a standardized model for studying vulnerabilities threats and defenses"):
  with members:
    - "ekiden a platform for confidentiality preserving trustworthy and performant smart contracts"
    - "a survey on ethereum systems security vulnerabilities attacks and defenses"
    - "security and privacy on blockchain"
    - "deconstructing blockchains a comprehensive survey on consensus membership and structure"
    - "truffle tests for free replaying ethereum smart contracts for transparency"
    - "exploring the attack surface of blockchain a systematic overview"
    - "strongchain transparent and collaborative proof of work consensus"
    - "a survey on consensus mechanisms and mining strategy management in blockchain networks"

Connected through hyperedge HE-2 (induced by source paper "presto a systematic framework for blockchain consensus protocols"):
  with members:
    - "oceanic games centralization risks and incentives in blockchain mining"
    - "weighted voting on the blockchain improving consensus in proof of stake protocols"
    - "blockchain trilemma solver algorand has dilemma over undecidable messages"
    - "strongchain transparent and collaborative proof of work consensus"
    - "a survey on consensus mechanisms and mining strategy management in blockchain networks"
    - "sok tools for game theoretic models of security for cryptocurrencies"
    - "incentives in ethereum s hybrid casper protocol"
    - "scilla a smart contract intermediate level language"

Connected through hyperedge HE-3 (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"
    - "a survey on consensus mechanisms and mining strategy management in blockchain networks"
    - "designing a blockchain based iot with ethereum swarm and lora the software solution to create high availability with minimal security risks"
    - "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-4 (induced by source paper "when energy trading meets blockchain in electrical power system the state of the art"):
  with members:
    - "decentralized p2p energy trading under network constraints in a low voltage network"
    - "on the applicability of distributed ledger architectures to peer to peer energy trading framework"
    - "peer to peer and community based markets a comprehensive review"
    - "peer to peer energytrade a distributed private energy trading platform"
    - "secure and privacy friendly local electricity trading and billing in smart grid"
    - "peer to peer energy trading with sustainable user participation a game theoretic approach"
    - "privacy preserving and efficient aggregation based on blockchain for power grid communications in smart communities"
    - "auction mechanisms in cloud fog computing resource allocation for public blockchain networks"

Connected through hyperedge HE-5 (induced by source paper "authentication and authorization for mobile iot devices using bio features recent advances and future trends"):
  with members:
    - "multimodal biometric authentication using choquet integral and genetic algorithm"
    - "a survey on behavioral biometric authentication on smartphones"
    - "deep learning based dynamic watermarking for secure signal authentication in the internet of things"
    - "partial face detection for continuous authentication"
    - "hmog new behavioral biometric features for continuous authentication of smartphone users"
    - "touchin sightless two factor authentication on multi touch mobile devices"
    - "touchalytics on the applicability of touchscreen input as a behavioral biometric for continuous authentication"
    - "a survey of biometric keystroke dynamics approaches security and challenges"

Connected through hyperedge HE-6 (induced by source paper "on the convergence of blockchain and internet of things iot technologies"):
  with members:
    - "hyperledger fabric a distributed operating system for permissioned blockchains"
    - "analysis of the communication traffic for blockchain synchronization of iot devices"
    - "blockchain based smart contracts a systematic mapping study"
    - "proof of work without all the work"
    - "blockchain in internet of things challenges and solutions"
    - "bitcoin ng a scalable blockchain protocol"
    - "majority is not enough bitcoin mining is vulnerable"

Connected through hyperedge HE-7 (induced by source paper "a privacy preserving accountable and spam resilient geo marketplace"):
  with members:
    - "modelchain decentralized privacy preserving healthcare predictive modeling framework on private blockchain networks"
    - "using block chain for peer to peer proof of location"

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)