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: "a first look at identity management schemes on the blockchain"
  Abstract: The emergence of distributed ledger technology (DLT) based upon a blockchain data structure, has given rise to new approaches to identity management that aim to upend dominant approaches to providing and consuming digital identities. These new approaches to identity management (IdM) propose to enhance decentralisation, transparency and user control in transactions that involve identity information; but, given the historical challenge to design IdM, can these new DLT-based schemes deliver on their lofty goals? We introduce the emerging landscape of DLT-based IdM, and evaluate three representative proposals: uPort; ShoCard; and Sovrin; using the analytic lens of a seminal framework that characterises the nature of successful IdM schemes.

Connected through hyperedge HE-1 (induced by source paper "security privacy in iot using machine learning blockchain threats countermeasures"):
  with members:
    - "machine learning in iot security current solutions and future challenges"
    - "on accurate and reliable anomaly detection for gas turbine combustors a deep learning approach"
    - "security services using blockchains a state of the art survey"
    - "a survey on the security of blockchain systems"
    - "secure mobile crowdsensing with deep learning"
    - "securing the internet of things in the age of machine learning and software defined networking"
    - "blockchain as a service an autonomous privacy preserving decentralized architecture for deep learning"
    - "sok security and privacy in machine learning"

Connected through hyperedge HE-2 (induced by source paper "a taxonomic approach to understanding emerging blockchain identity management systems"):
  with members:
    - "a decentralised digital identity architecture"
    - "verifiable anonymous identities and access control in permissioned blockchains"
    - "on the practicality of a smart contract pki"
    - "certledger a new pki model with certificate transparency based on blockchain"
    - "a privacy preserving system for data ownership using blockchain and distributed databases"
    - "blockchain technology overview"
    - "blockpki an automated resilient and transparent public key infrastructure"
    - "coconut threshold issuance selective disclosure credentials with applications to distributed ledgers"

Connected through hyperedge HE-3 (induced by source paper "tapestry a blockchain based service for trusted interaction online"):
  with members:
    - "ethical dimensions of visualization research"
    - "composite behavioral modeling for identity theft detection in online social networks"
    - "group anomaly detection using deep generative models"
    - "deep image retrieval learning global representations for image search"
    - "cnn image retrieval learns from bow unsupervised fine tuning with hard examples"
    - "facenet a unified embedding for face recognition and clustering"
    - "a primer on neural network models for natural language processing"
    - "distributed representations of words and phrases and their compositionality"

Connected through hyperedge HE-4 (induced by source paper "blockchain technologies for smart energy systems fundamentals challenges and solutions"):
  with members:
    - "peer to peer and community based markets a comprehensive review"
    - "implicit consensus blockchain with unbounded throughput"
    - "blockchain based smart contracts a systematic mapping study"
    - "untangling blockchain a data processing view of blockchain systems"

Connected through hyperedge HE-5 (induced by source paper "a decentralised digital identity architecture"):
  with members:
    - "can cryptocurrencies preserve privacy and comply with regulations"
    - "coconut threshold issuance selective disclosure credentials with applications to distributed ledgers"

Connected through hyperedge HE-6 (induced by source paper "self sovereign identity solutions the necessity of blockchain technology"):
  with members:
    - "deployment of a blockchain based self sovereign identity"
    - "private data system enabling self sovereign storage managed by executable choreographies"

Connected through hyperedge HE-7 (induced by source paper "full text search for verifiable credential metadata on distributed ledgers"):
  with members:
    - "a survey on essential components of a self sovereign identity"

Connected through hyperedge HE-8 (induced by source paper "blockchain based smart contracts applications and challenges"):
  with members:
    - "smart contract slas for dense small cell as a service"
    - "blockchain based smart contracts a systematic mapping study"
    - "secure and trustable electronic medical records sharing using blockchain"
    - "towards an ontology driven blockchain design for supply chain provenance"
    - "understanding modern banking ledgers through blockchain technologies future of transaction processing and smart contracts on the internet of money"

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)