human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "blockchain based smart contracts applications and challenges"):
  Abstract: A blockchain-based smart contract or a "smart contract" for short, is a computer program intended to digitally facilitate the negotiation or contractual terms directly between users when certain conditions are met. With the advance in blockchain technology, smart contracts are being used to serve a wide range of purposes ranging from self-managed identities on public blockchains to automating business collaboration on permissioned blockchains. In this paper, we present a comprehensive survey of smart contracts with a focus on existing applications and challenges they face.

Includes members:
  Member "a first look at identity management schemes on the blockchain":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "security privacy in iot using machine learning blockchain threats countermeasures")
  Member "smart contract slas for dense small cell as a service":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "smart contract based secure spectrum sharing in multi operators wireless communication networks")
  Member "blockchain based smart contracts a systematic mapping study":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "an overview on smart contracts challenges advances and platforms")
  Member "secure and trustable electronic medical records sharing using blockchain":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "attribute based multi signature and encryption for ehr management a blockchain based solution")
  Member "towards an ontology driven blockchain design for supply chain provenance":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "the security reference architecture for blockchains towards a standardized model for studying vulnerabilities threats and defenses")
  Member "understanding modern banking ledgers through blockchain technologies future of transaction processing and smart contracts on the internet of money":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "security analysis methods on ethereum smart contract vulnerabilities a survey")

Question: Please tell me which class the source paper 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.CY(Computers and Society)