human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "on profitability of nakamoto double spend"):
  Abstract: Nakamoto double spend strategy, described in Bitcoin foundational article, leads to total ruin with positive probability and does not make sense from the profitability point of view. The simplest strategy that can be profitable incorporates a stopping threshold when success is unlikely. We solve and compute the exact profitability for this strategy. We compute the minimal amount of the double spend that is profitable. For a given amount of the transaction, we determine the minimal number of confirmations to be requested by the recipient such that this double spend strategy is non-profitable. We find that this number of confirmations is only 1 or 2 for average transactions and a small hashrate of the attacker. This is substantially lower than the original Nakamoto numbers that are widely used and are only based on the success probability instead of the profitability.

Includes members:
  Member "profitable double spending attacks":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "markov processes in blockchain systems")
  Member "on profitability of selfish mining":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "selfish mining in ethereum")
  Member "on profitability of stubborn mining":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "bitcoin selfish mining and dyck words")
  Member "on profitability of trailing mining":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "selfish mining in ethereum")
  Member "double spend races":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "ant routing scalability for the lightning network")
  Member "an analysis of attacks on blockchain consensus":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "characterizing cryptocurrency exchange scams")
  Member "analysis of hashrate based double spending":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "joint time scheduling and transaction fee selection in blockchain based rf powered backscatter cognitive radio network")

Question: Please tell me which class the source paper 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)