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: "astraea a decentralized blockchain oracle"
  Abstract: The public blockchain was originally conceived to process monetary transactions in a peer-to-peer network while preventing double-spending. It has since been extended to numerous other applications including execution of programs that exist on the blockchain called "smart contracts." Smart contracts have a major limitation, namely they only operate on data that is on the blockchain. Trusted entities called oracles attest to external data in order to bring it onto the blockchain but they do so without the robust security guarantees that blockchains generally provide. This has the potential to turn oracles into centralized points-of-failure. To address this concern, this paper introduces Astraea, a decentralized oracle based on a voting game that decides the truth or falsity of propositions. Players fall into two roles: voters and certifiers. Voters play a low-risk/low-reward role that is resistant to adversarial manipulation while certifiers play a high-risk/high-reward role so they are required to play with a high degree of accuracy. This paper also presents a formal analysis of the parameters behind the system to measure the probability of an adversary with bounded funds being able to successfully manipulate the oracle's decision, that shows that the same parameters can be set to make manipulation arbitrarily difficult---a desirable feature for the system. Further, this analysis demonstrates that under those conditions a Nash equilibrium exists where all rational players are forced to behave honestly.

Connected through hyperedge HE-1 (induced by source paper "an overview on smart contracts challenges advances and platforms"):
  with members:
    - "the art of the scam demystifying honeypots in ethereum smart contracts"
    - "blockchain for internet of things a survey"
    - "evmfuzz differential fuzz testing of ethereum virtual machine"
    - "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"
    - "sabre protecting bitcoin against routing attacks"
    - "hunting the ethereum smart contract color inspired inspection of potential attacks"

Connected through hyperedge HE-2 (induced by source paper "a survey on ethereum systems security vulnerabilities attacks and defenses"):
  with members:
    - "security and privacy on blockchain"
    - "exploring the attack surface of blockchain a systematic overview"
    - "a survey on consensus mechanisms and mining strategy management in blockchain networks"
    - "metrics towards measuring cyber agility"
    - "selfish mining in ethereum"
    - "a survey of distributed consensus protocols for blockchain networks"
    - "finding the greedy prodigal and suicidal contracts at scale"
    - "ethir a framework for high level analysis of ethereum bytecode"

Connected through hyperedge HE-3 (induced by source paper "a survey on applications of game theory in blockchain"):
  with members:
    - "a survey on consensus mechanisms and mining strategy management in blockchain networks"
    - "security services using blockchains a state of the art survey"
    - "blockchain governance game"
    - "exchange of renewable energy among prosumers using blockchain with dynamic pricing"
    - "game of coins"
    - "delayed blockchain protocols"
    - "reward sharing schemes for stake pools"
    - "a survey on the security of blockchain systems"

Connected through hyperedge HE-4 (induced by source paper "securely trading unverifiable information without trust"):
  with members:
    - "a scalable verification solution for blockchains"
    - "water from two rocks maximizing the mutual information"
    - "betrayal distrust and rationality smart counter collusion contracts for verifiable cloud computing"
    - "smart contract templates essential requirements and design options"
    - "informed truthfulness in multi task peer prediction"
    - "crowdsourced judgement elicitation with endogenous proficiency"
    - "a new approach to practical active secure two party computation"

Connected through hyperedge HE-5 (induced by source paper "deco liberating web data using decentralized oracles for tls"):
  with members:
    - "raptor routing attacks on privacy in tor"
    - "augur a decentralized open source platform for prediction markets"

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)