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: "double spend races"
  Abstract: We correct the double spend race analysis given in Nakamoto's foundational Bitcoin article and give a closed-form formula for the probability of success of a double spend attack using the Regularized Incomplete Beta Function. We give a proof of the exponential decay on the number of confirmations, often cited in the literature, and find an asymptotic formula. Larger number of confirmations are necessary compared to those given by Nakamoto. We also compute the probability conditional to the known validation time of the blocks. This provides a finer risk analysis than the classical one.

Connected through hyperedge HE-1 (induced by source paper "ant routing scalability for the lightning network"):
  with members:
    - "topological analysis of bitcoin s lightning network"
    - "imbalance measure and proactive channel rebalancing algorithm for the lightning network"
    - "ant routing algorithm for the lightning network"
    - "routing cryptocurrency with the spider network"
    - "txprobe discovering bitcoin s network topology using orphan transactions"
    - "high throughput cryptocurrency routing in payment channel networks"
    - "settling payments fast and private efficient decentralized routing for path based transactions"

Connected through hyperedge HE-2 (induced by source paper "on profitability of nakamoto double spend"):
  with members:
    - "profitable double spending attacks"
    - "on profitability of selfish mining"
    - "on profitability of stubborn mining"
    - "on profitability of trailing mining"
    - "an analysis of attacks on blockchain consensus"
    - "analysis of hashrate based double spending"

Connected through hyperedge HE-3 (induced by source paper "on cyber risk management of blockchain networks a game theoretic approach"):
  with members:
    - "a survey on security and privacy issues of bitcoin"
    - "decentralized caching for content delivery based on blockchain a game theoretic perspective"
    - "an empirical analysis of smart contracts platforms applications and design patterns"
    - "untangling blockchain a data processing view of blockchain systems"
    - "bitcoin ng a scalable blockchain protocol"
    - "analysis of hashrate based double spending"
    - "real and complex monotone communication games"

Connected through hyperedge HE-4 (induced by source paper "on profitability of selfish mining"):
  with members:
    - "on profitability of stubborn mining"
    - "on profitability of trailing mining"
    - "majority is not enough bitcoin mining is vulnerable"

Connected through hyperedge HE-5 (induced by source paper "on profitability of trailing mining"):
  with members:
    - "on profitability of selfish mining"
    - "on profitability of stubborn mining"
    - "majority is not enough bitcoin mining is vulnerable"

Connected through hyperedge HE-6 (induced by source paper "on profitability of stubborn mining"):
  with members:
    - "on profitability of selfish mining"
    - "majority is not enough bitcoin mining is vulnerable"

Connected through hyperedge HE-7 (induced by source paper "a logic of blockchain updates"):
  with members:
    - "a knowledge based analysis of the blockchain protocol"

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)