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: "empirical vulnerability analysis of automated smart contracts security testing on blockchains"
  Abstract: The emerging blockchain technology supports decentralized computing paradigm shift and is a rapidly approaching phenomenon. While blockchain is thought primarily as the basis of Bitcoin, its application has grown far beyond cryptocurrencies due to the introduction of smart contracts. Smart contracts are self-enforcing pieces of software, which reside and run over a hosting blockchain. Using blockchain-based smart contracts for secure and transparent management to govern interactions (authentication, connection, and transaction) in Internet-enabled environments, mostly IoT, is a niche area of research and practice. However, writing trustworthy and safe smart contracts can be tremendously challenging because of the complicated semantics of underlying domain-specific languages and its testability. There have been high-profile incidents that indicate blockchain smart contracts could contain various code-security vulnerabilities, instigating financial harms. When it involves security of smart contracts, developers embracing the ability to write the contracts should be capable of testing their code, for diagnosing security vulnerabilities, before deploying them to the immutable environments on blockchains. However, there are only a handful of security testing tools for smart contracts. This implies that the existing research on automatic smart contracts security testing is not adequate and remains in a very stage of infancy. With a specific goal to more readily realize the application of blockchain smart contracts in security and privacy, we should first understand their vulnerabilities before widespread implementation. Accordingly, the goal of this paper is to carry out a far-reaching experimental assessment of current static smart contracts security testing tools, for the most widely used blockchain, the Ethereum and its domain-specific programming language, Solidity to provide the first...

Connected through hyperedge HE-1 (induced by source paper "smart contract development from the perspective of developers topics and issues discussed on social media"):
  with members:
    - "a survey on ethereum systems security vulnerabilities attacks and defenses"
    - "when energy trading meets blockchain in electrical power system the state of the art"
    - "slither a static analysis framework for smart contracts"
    - "what are the actual flaws in important smart contracts and how can we find them"
    - "verisolid correct by design smart contracts for ethereum"
    - "manticore a user friendly symbolic execution framework for binaries and smart contracts"
    - "tool demonstration fsolidm for designing secure ethereum smart contracts"
    - "finding the greedy prodigal and suicidal contracts at scale"

Connected through hyperedge HE-2 (induced by source paper "vyper a security comparison with solidity based on common vulnerabilities"):
  with members:
    - "a survey on ethereum systems security vulnerabilities attacks and defenses"
    - "verisolid correct by design smart contracts for ethereum"
    - "finding the greedy prodigal and suicidal contracts at scale"
    - "towards safer smart contracts a survey of languages and verification methods"
    - "vandal a scalable security analysis framework for smart contracts"
    - "securify practical security analysis of smart contracts"
    - "designing secure ethereum smart contracts a finite state machine based approach"

Connected through hyperedge HE-3 (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"
    - "blockchain technologies for the internet of things research issues and challenges"
    - "exploring the attack surface of blockchain a systematic overview"
    - "strongchain transparent and collaborative proof of work consensus"

Connected through hyperedge HE-4 (induced by source paper "a security reference architecture for blockchains"):
  with members:
    - "ekiden a platform for confidentiality preserving trustworthy and performant smart contracts"
    - "strongchain transparent and collaborative proof of work consensus"
    - "insight into insiders and it a survey of insider threat taxonomies analysis modeling and countermeasures"
    - "dfinity technology overview series consensus system"
    - "short paper towards more reliable bitcoin timestamps"
    - "the latest gossip on bft consensus"
    - "finding the greedy prodigal and suicidal contracts at scale"
    - "sabre protecting bitcoin against routing attacks"

Connected through hyperedge HE-5 (induced by source paper "security analysis methods on ethereum smart contract vulnerabilities a survey"):
  with members:
    - "easyflow keep ethereum away from overflow"
    - "a security case study for blockchain games"
    - "a hybrid formal verification system in coq for ensuring the reliability and security of ethereum based service smart contracts"
    - "finding the greedy prodigal and suicidal contracts at scale"
    - "ethir a framework for high level analysis of ethereum bytecode"
    - "formal process virtual machine for smart contracts verification"
    - "scilla a smart contract intermediate level language"
    - "a semantic framework for the security analysis of ethereum smart contracts"

Connected through hyperedge HE-6 (induced by source paper "smart contract development in practice trends issues and discussions on stack overflow"):
  with members:
    - "a survey on ethereum systems security vulnerabilities attacks and defenses"
    - "when energy trading meets blockchain in electrical power system the state of the art"
    - "slither a static analysis framework for smart contracts"
    - "transax a blockchain based decentralized forward trading energy exchange for transactive microgrids"
    - "what are the actual flaws in important smart contracts and how can we find them"
    - "verisolid correct by design smart contracts for ethereum"
    - "manticore a user friendly symbolic execution framework for binaries and smart contracts"
    - "tool demonstration fsolidm for designing secure ethereum smart contracts"

Connected through hyperedge HE-7 (induced by source paper "verisolid correct by design smart contracts for ethereum"):
  with members:
    - "tool demonstration fsolidm for designing secure ethereum smart contracts"
    - "finding the greedy prodigal and suicidal contracts at scale"
    - "ethir a framework for high level analysis of ethereum bytecode"
    - "a semantic framework for the security analysis of ethereum smart contracts"
    - "lolisa formal syntax and semantics for a subset of the solidity programming language"
    - "vandal a scalable security analysis framework for smart contracts"
    - "securify practical security analysis of smart contracts"
    - "executable operational semantics of solidity"

Connected through hyperedge HE-8 (induced by source paper "soliditycheck quickly detecting smart contract problems through regular expressions"):
  with members:
    - "safevm a safety verifier for ethereum smart contracts"
    - "finding the greedy prodigal and suicidal contracts at scale"
    - "contractfuzzer fuzzing smart contracts for vulnerability detection"
    - "a semantic framework for the security analysis of ethereum smart contracts"
    - "towards safer smart contracts a sequence learning approach to detecting security threats"
    - "towards safer smart contracts a sequence learning approach to detecting vulnerabilities"
    - "securify practical security analysis of smart contracts"
    - "under optimized smart contracts devour your money"

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)