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 for future smart grid a comprehensive survey"):
  Abstract: The concept of smart grid has been introduced as a new vision of the conventional power grid to figure out an efficient way of integrating green and renewable energy technologies. In this way, Internet-connected smart grid, also called energy Internet, is also emerging as an innovative approach to ensure the energy from anywhere at any time. The ultimate goal of these developments is to build a sustainable society. However, integrating and coordinating a large number of growing connections can be a challenging issue for the traditional centralized grid system. Consequently, the smart grid is undergoing a transformation to the decentralized topology from its centralized form. On the other hand, blockchain has some excellent features which make it a promising application for smart grid paradigm. In this paper, we have an aim to provide a comprehensive survey on application of blockchain in smart grid. As such, we identify the significant security challenges of smart grid scenarios that can be addressed by blockchain. Then, we present a number of blockchain-based recent research works presented in different literatures addressing security issues in the area of smart grid. We also summarize several related practical projects, trials, and products that have been emerged recently. Finally, we discuss essential research challenges and future directions of applying blockchain to smart grid security issues.

Includes members:
  Member "exploring the attack surface of blockchain a systematic overview":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "the security reference architecture for blockchains towards a standardized model for studying vulnerabilities threats and defenses")
  Member "an efficient blockchain based hierarchical authentication mechanism for energy trading in v2g environment":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "a review of blockchain based smart grid applications opportunities and future directions")
  Member "when energy trading meets blockchain in electrical power system the state of the art":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "smart contract development from the perspective of developers topics and issues discussed on social media")
  Member "energy crowdsourcing and peer to peer energy trading in blockchain enabled smart grids":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "peer to peer trading in electricity networks an overview")
  Member "blockchain based grid operation services for transactive energy systems":
    also connected through other hyperedges:
      (none)
  Member "blockchain technologies for smart energy systems fundamentals challenges and solutions":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "peer to peer trading in electricity networks an overview")
  Member "key management systems for smart grid advanced metering infrastructure a survey":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "lisa a lightweight and secure authentication mechanism for smart metering infrastructure")
  Member "a survey on the security of blockchain systems":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "an overview on smart contracts challenges advances and platforms")

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.CR(Cryptography and Security)