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 "repchain a reputation based secure fast and high incentive blockchain system via sharding"):
  Abstract: In today's blockchain system, designing a secure and high throughput on par with centralized payment system is a difficulty task. Sharding is one of the most worth expecting technologies to improve the system throughput when maintain high security level. However, the previous works have two main limitations: Firstly, the throughput of their random-based sharding system is not high enough due to not leveraging the heterogeneity among validators. Secondly, the incentive mechanism can be a huge overhead on their system without an appropriate scheme. We propose RepChain, a reputation-based secure, high incentive and fast blockchain system via sharding. RepChain utilizes reputation to explicitly characterize the heterogeneity among the validators and lay the foundation for the incentive mechanism. We novelly propose the double-chain architecture that including transaction chain and reputation chain. For transaction chain, a Raft-based Byzantine fault tolerant synchronous consensus with high resiliency and high throughput has been presented. For reputation chain, the collective signing has been utilized to achieve consensus on the reputation score and support the high throughput transaction chain with moderate generation speed. Moreover, we propose a reputation based sharding and leader selection scheme. To analyze the security of RepChain, we propose a recursive formula to calculate the epoch security within only O(km^2) time. Further more, we implement and evaluate RepChain on Amazon Web Service platform. The results show our solution can enhance both throughout and security level of the existing sharding-based blockchain system.

Includes members:
  Member "towards scaling blockchain systems via sharding":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "effective scaling of blockchain beyond consensus innovations and moore s law")
  Member "practical synchronous byzantine consensus":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "on probabilistic byzantine fault tolerance")
  Member "efficient synchronous byzantine consensus":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "on probabilistic byzantine fault tolerance")
  Member "enhancing bitcoin security and performance with strong consistency via collective signing":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "surface a practical blockchain consensus algorithm for real world networks")
  Member "xft practical fault tolerance beyond crashes":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "two more algorithms for randomized signature free asynchronous binary byzantine consensus with t n 3 and o n 2 messages and o 1 round expected termination")
  Member "bitcoin ng a scalable blockchain protocol":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "surface a practical blockchain consensus algorithm for real world networks")
  Member "centrally banked cryptocurrencies":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "on the feasibility of sybil attacks in shard based permissionless blockchains")

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)