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: "multi authority attribute based access control with smart contract"
  Abstract: Attribute-based access control makes access control decisions based on the assigned attributes of subjects and the access policies to protect objects by mediating operations from the subjects. Authority, which validates attributes of subjects, is one key component to facilitate attribute-based access control. In an increasingly decentralized society, multiple attributes possessed by subjects may need to be validated by multiple different authorities. This paper proposes a multi-authority attribute-based access control scheme by using Ethereum's smart contracts. In the proposed scheme, Ethereum smart contracts are created to define the interactions between data owner, data user, and multiple attribute authorities. A data user presents its attributes to different attribute authorities, and after successful validation of attributes, obtains attribute tokens from respective attribute authorities. After collecting enough attribute tokens, a smart contract will be executed to issue secret key to the data user to access the requested object. The smart contracts for multi-authority attribute-based access control have been prototyped in Solidity, and their performance has been evaluated on the Rinkeby Ethereum Testnet.

Connected through hyperedge HE-1 (induced by source paper "attribute based multi signature and encryption for ehr management a blockchain based solution"):
  with members:
    - "access control for electronic health records with hybrid blockchain edge architecture"
    - "b ride ride sharing with privacy preservation trust and fair payment atop public blockchain"
    - "blockchain based firmware update scheme tailored for autonomous vehicles"
    - "secure and trustable electronic medical records sharing using blockchain"

Connected through hyperedge HE-2 (induced by source paper "access control for electronic health records with hybrid blockchain edge architecture"):
  with members:
    - "a blockchain based architecture for traffic signal control systems"

Connected through hyperedge HE-3 (induced by source paper "leveraging protection and efficiency of query answering in heterogenous rdf data using blockchain"):
  with members:
    - "introducing a hybrid model of dea and data mining in evaluating efficiency case study bank branches"
    - "sustainable blockchain enabled services smart contracts"
    - "building an ontology for the domain of plant science using protege"
    - "blockchain inspired event recording system for autonomous vehicles"
    - "blockchain access control ecosystem for big data security"
    - "searching and establishment of s p o relationships for linked rdf graphs an adaptive approach"

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)