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: "blackchain scalability for resource constrained accountable vehicle to x communication"
  Abstract: In this paper, we propose a new Blockchain-based message and revocation accountability system called Blackchain. Combining a distributed ledger with existing mechanisms for security in V2X communication systems, we design a distributed event data recorder (EDR) that satisfies traditional accountability requirements by providing a compressed global state. Unlike previous approaches, our distributed ledger solution provides an accountable revocation mechanism without requiring trust in a single misbehavior authority, instead allowing a collaborative and transparent decision making process through Blackchain. This makes Blackchain an attractive alternative to existing solutions for revocation in a Security Credential Management System (SCMS), which suffer from the traditional disadvantages of PKIs, notably including centralized trust. Our proposal becomes scalable through the use of hierarchical consensus: individual vehicles dynamically create clusters, which then provide their consensus decisions as input for road-side units (RSUs), which in turn publish their results to misbehavior authorities. This authority, which is traditionally a single entity in the SCMS, responsible for the integrity of the entire V2X network, is now a set of authorities that transparently perform a revocation, whose result is then published in a global Blackchain state. This state can be used to prevent the issuance of certificates to previously malicious users, and also prevents the authority from misbehaving through the transparency implied by a global system state.

Connected through hyperedge HE-1 (induced by source paper "are distributed ledger technologies ready for smart transportation systems"):
  with members:
    - "likestarter a smart contract based social dao for crowdfunding"
    - "a distributed ledger based infrastructure for smart transportation system and social good"
    - "on the ethereum blockchain structure a complex networks theory perspective"
    - "orchestrating product provenance story when iota ecosystem meets the electronics supply chain space"
    - "a blockchain based flight data recorder for cloud accountability"
    - "iota feasibility and perspectives for enabling vehicular applications"
    - "multi level simulation of internet of things on smart territories"
    - "simulation of the internet of things"

Connected through hyperedge HE-2 (induced by source paper "blockchain for cities a systematic literature review"):
  with members:
    - "eductx a blockchain based higher education credit platform"
    - "providing privacy safety and security in iot based transactive energy systems using distributed ledgers"
    - "distributed protocols at the rescue for trustworthy online voting"
    - "deanonymisation of clients in bitcoin p2p network"

Connected through hyperedge HE-3 (induced by source paper "blockchain inspired event recording system for autonomous vehicles"):
  with members:
    - "securing vehicle to vehicle communications using blockchain through visible light and acoustic side channels"
    - "strong federations an interoperable blockchain solution to centralized third party risks"
    - "the miner s dilemma"

Connected through hyperedge HE-4 (induced by source paper "b fica blockchain based framework for auto insurance claim and adjudication"):
  with members:
    - "block4forensic an integrated lightweight blockchain framework for forensics applications of connected vehicles"
    - "blockchain a distributed solution to automotive security and privacy"

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)