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: "coconut threshold issuance selective disclosure credentials with applications to distributed ledgers"
  Abstract: We present Coconut, a novel selective disclosure credential scheme supporting distributed threshold issuance, public and private attributes, re-randomization, and multiple unlinkable selective attribute revelations. Coconut can be used by modern blockchains to ensure confidentiality, authenticity and availability even when a subset of credential issuing authorities are malicious or offline. We implement and evaluate a generic Coconut smart contract library for Chainspace and Ethereum; and present three applications related to anonymous payments, electronic petitions, and distribution of proxies for censorship resistance. Coconut uses short and computationally efficient credentials, and our evaluation shows that most Coconut cryptographic primitives take just a few milliseconds on average, with verification taking the longest time (10 milliseconds).

Connected through hyperedge HE-1 (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"
    - "a first look at identity management schemes on the blockchain"

Connected through hyperedge HE-2 (induced by source paper "zero knowledge proof of identity sybil resistant anonymous authentication on permissionless blockchains and incentive compatible strictly dominant cryptocurrencies"):
  with members:
    - "diversification across mining pools optimal mining strategies under pow"
    - "sok tools for game theoretic models of security for cryptocurrencies"
    - "impossibility of full decentralization in permissionless blockchains"
    - "dfinity technology overview series consensus system"
    - "a game theoretic analysis of shard based permissionless blockchains"
    - "be selfish and avoid dilemmas fork after withholding faw attacks on bitcoin"
    - "enhancing bitcoin security and performance with strong consistency via collective signing"
    - "keeping authorities honest or bust with decentralized witness cosigning"

Connected through hyperedge HE-3 (induced by source paper "threshold logical clocks for asynchronous distributed coordination and consensus"):
  with members:
    - "sok transparent dishonesty front running attacks on blockchain"
    - "validated asynchronous byzantine agreement with optimal resilience and asymptotically optimal time and word communication"
    - "blockmania from block dags to consensus"
    - "towards more reliable bitcoin timestamps"
    - "enhancing bitcoin security and performance with strong consistency via collective signing"
    - "hijacking bitcoin large scale network attacks on cryptocurrencies"
    - "on reducing the complexity of matrix clocks"
    - "secure history preservation through timeline entanglement"

Connected through hyperedge HE-4 (induced by source paper "asterisk auction based shared economy resolution system for blockchain"):
  with members:
    - "airtnt fair exchange payment for outsourced secure enclave computations"
    - "spoc secure payments for outsourced computations"
    - "chainspace a sharded smart contracts platform"

Connected through hyperedge HE-5 (induced by source paper "a decentralised digital identity architecture"):
  with members:
    - "can cryptocurrencies preserve privacy and comply with regulations"
    - "a first look at identity management schemes on the blockchain"

Connected through hyperedge HE-6 (induced by source paper "auditable credential anonymity revocation based on privacy preserving smart contracts"):
  with members:
    - "ekiden a platform for confidentiality preserving trustworthy and performant smart contracts"
    - "bitcoin ng a scalable blockchain protocol"

Connected through hyperedge HE-7 (induced by source paper "coconut e petition implementation"):
  with members:
    - "chainspace a sharded smart contracts platform"

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)