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: "the balance attack against proof of work blockchains the r3 testbed as an example"
  Abstract: In this paper, we identify a new form of attack, called the Balance attack, against proof-of-work blockchain systems. The novelty of this attack consists of delaying network communications between multiple subgroups of nodes with balanced mining power. Our theoretical analysis captures the precise tradeoff between the network delay and the mining power of the attacker needed to double spend in Ethereum with high probability. #R##N#We quantify our probabilistic analysis with statistics taken from the R3 consortium, and show that a single machine needs 20 minutes to attack the consortium. Finally, we run an Ethereum private chain in a distributed system with similar settings as R3 to demonstrate the feasibility of the approach, and discuss the application of the Balance attack to Bitcoin. Our results clearly confirm that main proof-of-work blockchain protocols can be badly suited for consortium blockchains.

Connected through hyperedge HE-1 (induced by source paper "continuous time analysis of the bitcoin and prism backbone protocols"):
  with members:
    - "on analysis of the bitcoin and prism backbone protocols"
    - "deconstructing the blockchain to approach physical limits"
    - "scaling nakamoto consensus to thousands of transactions per second"
    - "bitcoin ng a scalable blockchain protocol"

Connected through hyperedge HE-2 (induced by source paper "on analysis of the bitcoin and prism backbone protocols"):
  with members:
    - "deconstructing the blockchain to approach physical limits"
    - "scaling nakamoto consensus to thousands of transactions per second"
    - "optimal selfish mining strategies in bitcoin"
    - "bitcoin ng a scalable blockchain protocol"
    - "bitcoin meets strong consistency"

Connected through hyperedge HE-3 (induced by source paper "prism scaling bitcoin by 10 000x"):
  with members:
    - "deconstructing the blockchain to approach physical limits"
    - "scaling nakamoto consensus to thousands of transactions per second"
    - "ohie blockchain scaling made simple"
    - "blockchains consensus protocols in the wild"
    - "bitcoin ng a scalable blockchain protocol"

Connected through hyperedge HE-4 (induced by source paper "a survey on security and privacy issues of bitcoin"):
  with members:
    - "concurrency and privacy with payment channel networks"
    - "dandelion redesigning the bitcoin network for anonymity"
    - "consensus in the age of blockchains"
    - "when the cookie meets the blockchain privacy risks of web payments via cryptocurrencies"
    - "be selfish and avoid dilemmas fork after withholding faw attacks on bitcoin"
    - "socially optimal mining pools"
    - "hijacking bitcoin routing attacks on cryptocurrencies"
    - "blockchain mining games"

Connected through hyperedge HE-5 (induced by source paper "ohie blockchain scaling made simple"):
  with members:
    - "decentralization in bitcoin and ethereum networks"
    - "deconstructing the blockchain to approach physical limits"
    - "scaling nakamoto consensus to thousands of transactions per second"
    - "chainspace a sharded smart contracts platform"
    - "revisiting fast practical byzantine fault tolerance"
    - "hijacking bitcoin routing attacks on cryptocurrencies"
    - "enhancing bitcoin security and performance with strong consistency via collective signing"
    - "bitcoin ng a scalable blockchain protocol"

Connected through hyperedge HE-6 (induced by source paper "a survey on the security of blockchain systems"):
  with members:
    - "an empirical analysis of linkability in the monero blockchain"
    - "under optimized smart contracts devour your money"
    - "an empirical analysis of smart contracts platforms applications and design patterns"
    - "hijacking bitcoin routing attacks on cryptocurrencies"
    - "majority is not enough bitcoin mining is vulnerable"
    - "traveling the silk road a measurement analysis of a large anonymous online marketplace"

Connected through hyperedge HE-7 (induced by source paper "the looming threat of china an analysis of chinese influence on bitcoin"):
  with members:
    - "a survey on security and privacy issues of bitcoin"
    - "when the cookie meets the blockchain privacy risks of web payments via cryptocurrencies"
    - "deanonymisation of clients in bitcoin p2p network"
    - "majority is not enough bitcoin mining is vulnerable"
    - "analysis of bitcoin pooled mining reward systems"

Connected through hyperedge HE-8 (induced by source paper "deconstructing the blockchain to approach physical limits"):
  with members:
    - "scaling nakamoto consensus to thousands of transactions per second"
    - "enhancing bitcoin security and performance with strong consistency via collective signing"
    - "solida a blockchain protocol based on reconfigurable byzantine consensus"
    - "bitcoin meets strong consistency"

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.DC(Distributed, Parallel, and Cluster Computing)