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: "txprobe discovering bitcoin s network topology using orphan transactions"
  Abstract: Bitcoin relies on a peer-to-peer overlay network to broadcast transactions and blocks. From the viewpoint of network measurement, we would like to observe this topology so we can characterize its performance, fairness and robustness. However, this is difficult because Bitcoin is deliberately designed to hide its topology from onlookers. Knowledge of the topology is not in itself a vulnerability, although it could conceivably help an attacker performing targeted eclipse attacks or to deanonymize transaction senders. #R##N#In this paper we present TxProbe, a novel technique for reconstructing the Bitcoin network topology. TxProbe makes use of peculiarities in how Bitcoin processes out of order, or "orphaned" transactions. We conducted experiments on Bitcoin testnet that suggest our technique reconstructs topology with precision and recall surpassing 90%. We also used TxProbe to take a snapshot of the Bitcoin testnet in just a few hours. TxProbe may be useful for future measurement campaigns of Bitcoin or other cryptocurrency networks.

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"
    - "high throughput cryptocurrency routing in payment channel networks"
    - "double spend races"
    - "settling payments fast and private efficient decentralized routing for path based transactions"

Connected through hyperedge HE-2 (induced by source paper "all that glitters is not bitcoin unveiling the centralized nature of the btc ip network"):
  with members:
    - "decentralization in bitcoin and ethereum networks"
    - "digging into browser based crypto mining"
    - "block arrivals in the bitcoin blockchain"
    - "an evaluation of the security of the bitcoin peer to peer network"

Connected through hyperedge HE-3 (induced by source paper "hotpow finality from proof of work quorums"):
  with members:
    - "all that glitters is not bitcoin unveiling the centralized nature of the btc ip network"
    - "squirrl automating attack discovery on blockchain incentive mechanisms with deep reinforcement learning"
    - "the consensus number of a cryptocurrency"
    - "consensus in the age of blockchains"
    - "bobtail a proof of work target that minimizes blockchain mining variance draft"
    - "hijacking bitcoin routing attacks on cryptocurrencies"
    - "blockchain mining games"
    - "enhancing bitcoin security and performance with strong consistency via collective signing"

Connected through hyperedge HE-4 (induced by source paper "bandwidth efficient transaction relay for bitcoin"):
  with members:
    - "dandelion lightweight cryptocurrency networking with formal anonymity guarantees"
    - "bitcoin ng a scalable blockchain protocol"
    - "multi party set reconciliation using characteristic polynomials"
    - "deanonymisation of clients in bitcoin p2p network"
    - "bitcoin transaction malleability and mtgox"
    - "majority is not enough bitcoin mining is vulnerable"
    - "simple multi party set reconciliation"
    - "hosting byzantine fault tolerant services on a chord ring"

Connected through hyperedge HE-5 (induced by source paper "kriptosare gen a dockerized bitcoin testbed analysis of server performance"):
  with members:
    - "bitcoin over tor isn t a good idea"

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)