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 "the security reference architecture for blockchains towards a standardized model for studying vulnerabilities threats and defenses"):
  Abstract: Due to their specific features, such as decentralization and immutability, blockchains have become popular in recent years. Blockchains are full-stack distributed systems in terms of realization, where security is a critical factor for their success. However, despite increasing popularity and adoption, there is a lack of standardized models to study security threats related to blockchains in a similar fashion as was done, e.g., in the area of cloud computing. To fill this gap, the main focus of our work is to systematize the knowledge about security and privacy aspects of blockchains, and thus contribute to the standardization of this domain. #R##N#To this end, we propose the security reference architecture for blockchains, which utilizes a stacked model (similar to the ISO/OSI) that demonstrates the nature and hierarchy of various security and privacy threats. The model contains four layers: (1) the network layer, (2) the consensus layer, (3) the replicated state machine layer, and (4) the application layer. At each of these layers, we identify known security threats, their origin as well as mitigation techniques or countermeasures. % while we discuss the costs and impact of particular countermeasures. Although a similar model has already been used in previous work to serve as a general outline of the blockchain infrastructure, we adapt it for the purpose of studying security threats in this domain. Further, we propose a blockchain-specific version of the threat-risk assessment standard ISO/IEC 15408 by embedding the stacked model into this standard. Finally, following our stacked model and its categorization, we provide an extensive survey of blockchain-oriented and related research as well as its applications.

Includes members:
  Member "ekiden a platform for confidentiality preserving trustworthy and performant smart contracts":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "on the convergence of artificial intelligence and distributed ledger technology a scoping review and future research agenda")
  Member "a survey on ethereum systems security vulnerabilities attacks and defenses":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "smart contract development from the perspective of developers topics and issues discussed on social media")
  Member "security and privacy on blockchain":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "a survey on ethereum systems security vulnerabilities attacks and defenses")
  Member "deconstructing blockchains a comprehensive survey on consensus membership and structure":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "a survey of distributed consensus protocols for blockchain networks")
  Member "truffle tests for free replaying ethereum smart contracts for transparency":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "mutation testing of smart contracts at scale")
  Member "blockchain technologies for the internet of things research issues and challenges":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "presto a systematic framework for blockchain consensus protocols")
  Member "exploring the attack surface of blockchain a systematic overview":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "a survey on ethereum systems security vulnerabilities attacks and defenses")
  Member "strongchain transparent and collaborative proof of work consensus":
    also connected through other hyperedges:
      - Hyperedge HE-8 (induced by source paper "presto a systematic framework for blockchain consensus protocols")

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)