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: "a survey on security and privacy issues of bitcoin"
  Abstract: Bitcoin is a popular  cryptocurrency  that records all transactions in a distributed append-only public ledger called  blockchain . The security of Bitcoin heavily relies on the incentive-compatible proof-of-work (PoW) based distributed consensus protocol, which is run by the network nodes called  miners . In exchange for the incentive, the miners are expected to maintain the blockchain honestly. Since its launch in 2009, Bitcoin economy has grown at an enormous rate, and it is now worth about 150 billions of dollars. This exponential growth in the market value of bitcoins motivate adversaries to exploit weaknesses for profit, and researchers to discover new vulnerabilities in the system, propose countermeasures, and predict upcoming trends. In this paper, we present a systematic survey that covers the security and privacy aspects of Bitcoin. We start by giving an overview of the Bitcoin system and its major components along with their functionality and interactions within the system. We review the existing vulnerabilities in Bitcoin and its major underlying technologies such as blockchain and PoW-based consensus protocol. These vulnerabilities lead to the execution of various security threats to the standard functionality of Bitcoin. We then investigate the feasibility and robustness of the state-of-the-art security solutions. Additionally, we discuss the current anonymity considerations in Bitcoin and the privacy-related threats to Bitcoin users along with the analysis of the existing privacy-preserving solutions. Finally, we summarize the critical open challenges, and we suggest directions for future research towards provisioning stringent security and privacy solutions for Bitcoin.

Connected through hyperedge HE-1 (induced by source paper "on the feasibility of sybil attacks in shard based permissionless blockchains"):
  with members:
    - "polyshard coded sharding achieves linearly scaling efficiency and security simultaneously"
    - "chain of trust can trusted hardware help scaling blockchains"
    - "towards scaling blockchain systems via sharding"
    - "lagrange coded computing optimal design for resiliency security and privacy"
    - "blockchain mining games"
    - "enhancing bitcoin security and performance with strong consistency via collective signing"
    - "solida a blockchain protocol based on reconfigurable byzantine consensus"
    - "centrally banked cryptocurrencies"

Connected through hyperedge HE-2 (induced by source paper "nonlinear blockchain scalability a game theoretic perspective"):
  with members:
    - "a survey on applications of game theory in blockchain"
    - "security services using blockchains a state of the art survey"

Connected through hyperedge HE-3 (induced by source paper "correlations of multi input monero transactions"):
  with members:
    - "bitcoinheist topological data analysis for ransomware detection on the bitcoin blockchain"

Connected through hyperedge HE-4 (induced by source paper "the security reference architecture for blockchains towards a standardized model for studying vulnerabilities threats and defenses"):
  with members:
    - "ekiden a platform for confidentiality preserving trustworthy and performant smart contracts"
    - "a survey on ethereum systems security vulnerabilities attacks and defenses"
    - "security and privacy on blockchain"
    - "deconstructing blockchains a comprehensive survey on consensus membership and structure"
    - "truffle tests for free replaying ethereum smart contracts for transparency"
    - "blockchain technologies for the internet of things research issues and challenges"
    - "exploring the attack surface of blockchain a systematic overview"
    - "strongchain transparent and collaborative proof of work consensus"

Connected through hyperedge HE-5 (induced by source paper "a survey on consensus mechanisms and mining strategy management in blockchain networks"):
  with members:
    - "decentralization in bitcoin and ethereum networks"
    - "information and communications technologies for sustainable development goals state of the art needs and perspectives"
    - "a scale out blockchain for value transfer with spontaneous sharding"
    - "on cyber risk management of blockchain networks a game theoretic approach"
    - "scaling nakamoto consensus to thousands of transactions per second"
    - "competitive data trading in wireless powered internet of things iot crowdsensing systems with blockchain"
    - "blockchained on device federated learning"
    - "decentralized caching for content delivery based on blockchain a game theoretic perspective"

Connected through hyperedge HE-6 (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-7 (induced by source paper "exploring the attack surface of blockchain a systematic overview"):
  with members:
    - "scalable byzantine consensus via hardware assisted secret sharing"
    - "security services using blockchains a state of the art survey"
    - "a survey on the security of blockchain systems"
    - "an empirical analysis of anonymity in zcash"
    - "towards blockchain driven secure and transparent audit logs"
    - "end to end analysis of in browser cryptojacking"
    - "linbft linear communication byzantine fault tolerance for public blockchains"
    - "the impact of uncle rewards on selfish mining in ethereum"

Connected through hyperedge HE-8 (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"

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)