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: "private data objects an overview"
  Abstract: We present Private Data Objects (PDOs), a technology that enables mutually untrusted parties to run smart contracts over private data. PDOs result from the integration of a distributed ledger and Intel Secure Guard Extensions (SGX). In particular, contracts run off-ledger in secure enclaves using Intel SGX, which preserves data confidentiality, execution integrity and enforces data access policies (as opposed to raw data access). A distributed ledger verifies and records transactions produced by PDOs, in order to provide a single authoritative instance of such objects. This allows contracting parties to retrieve and check data related to contract and enclave instances, as well as to serialize and commit contract state updates. The design and the development of PDOs is an ongoing research effort, and open source code is available and hosted by Hyperledger Labs [5, 7].

Connected through hyperedge HE-1 (induced by source paper "enforcing private data usage control with blockchain and attested off chain contract execution"):
  with members:
    - "ekiden a platform for confidentiality preserving trustworthy and performant smart contracts"
    - "chiron privacy preserving machine learning as a service"
    - "sok sanitizing for security"
    - "chexnet radiologist level pneumonia detection on chest x rays with deep learning"
    - "use privacy in data driven systems theory and experiments with machine learnt programs"
    - "enhancing bitcoin security and performance with strong consistency via collective signing"
    - "enigma decentralized computation platform with guaranteed privacy"

Connected through hyperedge HE-2 (induced by source paper "ekiden a platform for confidentiality preserving trustworthy and performant smart contracts"):
  with members:
    - "a scalable verification solution for blockchains"
    - "instantaneous decentralized poker"
    - "software grand exposure sgx cache attacks are practical"
    - "malware guard extension using sgx to conceal cache attacks"
    - "stealing machine learning models via prediction apis"
    - "membership inference attacks against machine learning models"

Connected through hyperedge HE-3 (induced by source paper "s faas trustworthy and accountable function as a service using intel sgx"):
  with members:
    - "ekiden a platform for confidentiality preserving trustworthy and performant smart contracts"
    - "sgxpectre stealing intel secrets from sgx enclaves via speculative execution"
    - "integrating remote attestation with transport layer security"
    - "sgx aware container orchestration for heterogeneous clusters"
    - "software grand exposure sgx cache attacks are practical"
    - "inferring fine grained control flow inside sgx enclaves with branch shadowing"
    - "proof of luck an efficient blockchain consensus protocol"

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)