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: "incentives in ethereum s hybrid casper protocol"
  Abstract: We present an overview of hybrid Casper the Friendly Finality Gadget (FFG): a Proof-of-Stake checkpointing protocol overlaid onto Ethereum's Proof-of-Work blockchain. We describe its core functionalities and reward scheme, and explore its properties. Our findings indicate that Casper's implemented incentives mechanism ensures liveness, while providing safety guarantees that improve over standard Proof-of-Work protocols. Based on a minimal-impact implementation of the protocol as a smart contract on the blockchain, we discuss additional issues related to parametrisation, funding, throughput and network overhead and detect potential limitations.

Connected through hyperedge HE-1 (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"
    - "blockchain technologies for the internet of things research issues and challenges"
    - "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"
    - "scilla a smart contract intermediate level language"

Connected through hyperedge HE-2 (induced by source paper "weighted voting on the blockchain improving consensus in proof of stake protocols"):
  with members:
    - "reward sharing schemes for stake pools"
    - "hyperledger fabric a distributed operating system for permissioned blockchains"
    - "rethinking blockchain security position paper"
    - "betting on blockchain consensus with fantomette"
    - "consensus in the age of blockchains"
    - "multiplicative weights update with constant step size in congestion games convergence limit cycles and chaos"
    - "casper the friendly finality gadget"
    - "untangling blockchain a data processing view of blockchain systems"

Connected through hyperedge HE-3 (induced by source paper "blockchain powered collaboration in heterogeneous swarms of robots"):
  with members:
    - "a survey on consensus mechanisms and mining strategy management in blockchain networks"
    - "hyperledger fabric a distributed operating system for permissioned blockchains"
    - "a survey on the security of blockchain systems"
    - "a byzantine fault tolerant ordering service for the hyperledger fabric blockchain platform"
    - "casper the friendly finality gadget"
    - "the blockchain a new framework for robotic swarm systems"
    - "end to end learning for self driving cars"
    - "cryptocurrencies without proof of work"

Connected through hyperedge HE-4 (induced by source paper "oceanic games centralization risks and incentives in blockchain mining"):
  with members:
    - "weighted voting on the blockchain improving consensus in proof of stake protocols"
    - "reward sharing schemes for stake pools"
    - "compounding of wealth in proof of stake cryptocurrencies"
    - "bitcoin a natural oligopoly"
    - "socially optimal mining pools"
    - "blockchain mining games"
    - "cryptocurrencies without proof of work"
    - "the miner s dilemma"

Connected through hyperedge HE-5 (induced by source paper "the economics of smart contracts"):
  with members:
    - "blockchain meets database design and implementation of a blockchain relational database"
    - "empirically analyzing ethereum s gas mechanism"
    - "broken metre attacking resource metering in evm"
    - "an adaptive gas cost mechanism for ethereum to defend against under priced dos attacks"
    - "casper the friendly finality gadget"

Connected through hyperedge HE-6 (induced by source paper "building scalable decentralized payment systems"):
  with members:
    - "a scalable verification solution for blockchains"
    - "atomic cross chain swaps"
    - "consensus in the age of blockchains"
    - "casper the friendly finality gadget"
    - "invertible bloom lookup tables"

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)