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: "on the ethereum blockchain structure a complex networks theory perspective"
  Abstract: In this paper, we analyze the Ethereum blockchain using the complex networks modeling framework. Accounts acting on the blockchain are represented as nodes, while the interactions among these accounts, recorded on the blockchain, are treated as links in the network. Using this representation, it is possible to derive interesting mathematical characteristics that improve the understanding of the actual interactions happening in the blockchain. Not only, by looking at the history of the blockchain, it is possible to verify if radical changes in the blockchain evolution happened.

Connected through hyperedge HE-1 (induced by source paper "are distributed ledger technologies ready for smart transportation systems"):
  with members:
    - "likestarter a smart contract based social dao for crowdfunding"
    - "a distributed ledger based infrastructure for smart transportation system and social good"
    - "orchestrating product provenance story when iota ecosystem meets the electronics supply chain space"
    - "a blockchain based flight data recorder for cloud accountability"
    - "iota feasibility and perspectives for enabling vehicular applications"
    - "blackchain scalability for resource constrained accountable vehicle to x communication"
    - "multi level simulation of internet of things on smart territories"
    - "simulation of the internet of things"

Connected through hyperedge HE-2 (induced by source paper "a distributed ledger based infrastructure for smart transportation system and social good"):
  with members:
    - "likestarter a smart contract based social dao for crowdfunding"
    - "idmob iot data marketplace on blockchain"
    - "a blockchain based flight data recorder for cloud accountability"
    - "towards blockchain based auditable storage and sharing of iot data"
    - "ipfs content addressed versioned p2p file system"

Connected through hyperedge HE-3 (induced by source paper "fast session resumption in dtls for mobile communications"):
  with members:
    - "tracking users across the web via tls session resumption"
    - "multi level simulation of internet of things on smart territories"
    - "a survey on handover management in mobility architectures"
    - "simulation of the internet of things"

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)