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: "enforcing private data usage control with blockchain and attested off chain contract execution"
  Abstract: The abundance of rich varieties of data is enabling many transformative applications of big data analytics that have profound societal impacts. However, there are also increasing concerns regarding the improper use of individual users' private data. Many argue that the technology that customizes our experience in the cyber domain is threatening the fundamental civil right to privacy. #R##N#In this paper, we propose PrivacyGuard, a system that leverages smart contract in blockchain and trusted execution environment to enable individuals' control over other parties' access and use of their private data. In our design, smart contracts are used to specify data usage policy (i.e. who can use what data under which conditions along with how the data can be used), while the distributed ledger is used to keep an irreversible and non-repudiable record of data usage. To address the contract execution efficiency problem, as well as to prevent exposing user data on the publicly viewable blockchain, we construct a novel off-chain contract execution engine which realizes trustworthy contract execution off-chain in an trusted execution environment (TEE). By running the contract program inside a hardware-assisted TEE, the proposed off-chain trustworthy contract execution improves system efficiency significantly, as its correctness does not rely on distributed consensus which essentially requires the contract program be executed on all miner nodes. In order to leverage TEE in off-chain execution, PrivacyGuard has to several technical challenges such as synchronous function completion and scalability mitigation in blockchain platform. We build and deploy a prototype of PrivacyGuard using Ethereum and Intel SGX, and our experiments demonstrate the feasibility to support data-intensive applications using data from a large number of users.

Connected through hyperedge HE-1 (induced by source paper "energy aware demand selection and allocation for real time iot data trading"):
  with members:
    - "towards secure and decentralized sharing of iot data"
    - "a conceptual marketplace model for iot generated personal data"
    - "a decentralized iot data marketplace"
    - "idmob iot data marketplace on blockchain"
    - "mind my value a decentralized infrastructure for fair and trusted iot data trading"
    - "blockchain enabled data marketplace design and challenges"
    - "distributed approximation algorithms for the multiple knapsack problem"
    - "allocation of heterogeneous resources of an iot device to flexible services"

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)