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: "when the cookie meets the blockchain privacy risks of web payments via cryptocurrencies"
  Abstract: We show how third-party web trackers can deanonymize users of cryptocurrencies. We present two distinct but complementary attacks. On most shopping websites, third party trackers receive information about user purchases for purposes of advertising and analytics. We show that, if the user pays using a cryptocurrency, trackers typically possess enough information about the purchase to uniquely identify the transaction on the blockchain, link it to the user's cookie, and further to the user's real identity. Our second attack shows that if the tracker is able to link two purchases of the same user to the blockchain in this manner, it can identify the user's entire cluster of addresses and transactions on the blockchain, even if the user employs blockchain anonymity techniques such as CoinJoin. The attacks are passive and hence can be retroactively applied to past purchases. We discuss several mitigations, but none are perfect.

Connected through hyperedge HE-1 (induced by source paper "sok blockchain technology and its potential use cases"):
  with members:
    - "decentralization in bitcoin and ethereum networks"
    - "hunting the ethereum smart contract color inspired inspection of potential attacks"
    - "a survey on security and privacy issues of bitcoin"
    - "a new look at the refund mechanism in the bitcoin payment protocol"
    - "consensus in the age of blockchains"
    - "solida a blockchain protocol based on reconfigurable byzantine consensus"
    - "bitcoin ng a scalable blockchain protocol"
    - "a first look at the usability of bitcoin key management"

Connected through hyperedge HE-2 (induced by source paper "blockchain and the future of the internet a comprehensive review"):
  with members:
    - "applications of blockchain technology beyond cryptocurrency"
    - "an experiment in distributed internet address management using blockchains"
    - "betrayal distrust and rationality smart counter collusion contracts for verifiable cloud computing"
    - "securing vehicle to vehicle communications using blockchain through visible light and acoustic side channels"
    - "blockchain in internet of things challenges and solutions"
    - "understanding modern banking ledgers through blockchain technologies future of transaction processing and smart contracts on the internet of money"
    - "online social networks threats and solutions"

Connected through hyperedge HE-3 (induced by source paper "blockchain mutability challenges and proposed solutions"):
  with members:
    - "redactable blockchain in the permissionless setting"
    - "mof bc a memory optimized and flexible blockchain for large scale networks"
    - "blockchains consensus protocols in the wild"
    - "an empirical analysis of smart contracts platforms applications and design patterns"
    - "enigma decentralized computation platform with guaranteed privacy"
    - "bitcoin transaction graph analysis"
    - "deanonymisation of clients in bitcoin p2p network"

Connected through hyperedge HE-4 (induced by source paper "safeguarding the evidential value of forensic cryptocurrency investigations"):
  with members:
    - "ransomware payments in the bitcoin ecosystem"
    - "an empirical analysis of anonymity in zcash"
    - "an empirical analysis of linkability in the monero blockchain"
    - "blocksci design and applications of a blockchain analysis platform"
    - "counterfactual explanations without opening the black box automated decisions and the gdpr"
    - "the unreasonable effectiveness of address clustering"

Connected through hyperedge HE-5 (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"
    - "be selfish and avoid dilemmas fork after withholding faw attacks on bitcoin"
    - "socially optimal mining pools"
    - "the balance attack against proof of work blockchains the r3 testbed as an example"
    - "hijacking bitcoin routing attacks on cryptocurrencies"
    - "blockchain mining games"

Connected through hyperedge HE-6 (induced by source paper "election with bribed voter uncertainty hardness and approximation algorithm"):
  with members:
    - "possible winners in noisy elections"
    - "complexity of manipulation bribery and campaign management in bucklin and fallback voting"
    - "determining possible and necessary winners under common voting rules given partial orders"
    - "taking the final step to a full dichotomy of the possible winner problem in pure scoring rules"
    - "multimode control attacks on elections"
    - "the complexity of manipulating k approval elections"
    - "towards a dichotomy for the possible winner problem in elections based on scoring rules"
    - "how hard is bribery in elections"

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"
    - "the balance attack against proof of work blockchains the r3 testbed as an example"
    - "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 "can cryptocurrencies preserve privacy and comply with regulations"):
  with members:
    - "an empirical analysis of anonymity in zcash"
    - "when a small leak sinks a great ship deanonymizing tor hidden service users through bitcoin transactions analysis"

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)