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: "securify practical security analysis of smart contracts"
  Abstract: Permissionless blockchains allow the execution of arbitrary programs (called smart contracts), enabling mutually untrusted entities to interact without relying on trusted third parties. Despite their potential, repeated security concerns have shaken the trust in handling billions of USD by smart contracts. #R##N#To address this problem, we present Securify, a security analyzer for Ethereum smart contracts that is scalable, fully automated, and able to prove contract behaviors as safe/unsafe with respect to a given property. Securify's analysis consists of two steps. First, it symbolically analyzes the contract's dependency graph to extract precise semantic information from the code. Then, it checks compliance and violation patterns that capture sufficient conditions for proving if a property holds or not. To enable extensibility, all patterns are specified in a designated domain-specific language. #R##N#Securify is publicly released, it has analyzed >18K contracts submitted by its users, and is regularly used to conduct security audits by experts. We present an extensive evaluation of Securify over real-world Ethereum smart contracts and demonstrate that it can effectively prove the correctness of smart contracts and discover critical violations.

Connected through hyperedge HE-1 (induced by source paper "an overview on smart contracts challenges advances and platforms"):
  with members:
    - "the art of the scam demystifying honeypots in ethereum smart contracts"
    - "blockchain for internet of things a survey"
    - "evmfuzz differential fuzz testing of ethereum virtual machine"
    - "tool demonstration fsolidm for designing secure ethereum smart contracts"
    - "finding the greedy prodigal and suicidal contracts at scale"
    - "ethir a framework for high level analysis of ethereum bytecode"
    - "sabre protecting bitcoin against routing attacks"
    - "hunting the ethereum smart contract color inspired inspection of potential attacks"

Connected through hyperedge HE-2 (induced by source paper "smart contract development from the perspective of developers topics and issues discussed on social media"):
  with members:
    - "a survey on ethereum systems security vulnerabilities attacks and defenses"
    - "when energy trading meets blockchain in electrical power system the state of the art"
    - "slither a static analysis framework for smart contracts"
    - "what are the actual flaws in important smart contracts and how can we find them"
    - "verisolid correct by design smart contracts for ethereum"
    - "manticore a user friendly symbolic execution framework for binaries and smart contracts"
    - "tool demonstration fsolidm for designing secure ethereum smart contracts"
    - "finding the greedy prodigal and suicidal contracts at scale"

Connected through hyperedge HE-3 (induced by source paper "ae gis shielding vulnerable smart contracts against attacks"):
  with members:
    - "slither a static analysis framework for smart contracts"
    - "soliditycheck quickly detecting smart contract problems through regular expressions"
    - "harvey a greybox fuzzer for smart contracts"
    - "exploiting the laws of order in smart contracts"
    - "finding the greedy prodigal and suicidal contracts at scale"
    - "contractfuzzer fuzzing smart contracts for vulnerability detection"
    - "a semantic framework for the security analysis of ethereum smart contracts"
    - "towards safer smart contracts a sequence learning approach to detecting security threats"

Connected through hyperedge HE-4 (induced by source paper "vyper a security comparison with solidity based on common vulnerabilities"):
  with members:
    - "a survey on ethereum systems security vulnerabilities attacks and defenses"
    - "verisolid correct by design smart contracts for ethereum"
    - "finding the greedy prodigal and suicidal contracts at scale"
    - "empirical vulnerability analysis of automated smart contracts security testing on blockchains"
    - "towards safer smart contracts a survey of languages and verification methods"
    - "vandal a scalable security analysis framework for smart contracts"
    - "designing secure ethereum smart contracts a finite state machine based approach"

Connected through hyperedge HE-5 (induced by source paper "formalising and verifying smart contracts with solidifier a bounded model checker for solidity"):
  with members:
    - "smt friendly formalization of the solidity memory model"
    - "ekiden a platform for confidentiality preserving trustworthy and performant smart contracts"
    - "solc verify a modular verifier for solidity smart contracts"
    - "a semantic framework for the security analysis of ethereum smart contracts"
    - "hyperledger fabric a distributed operating system for permissioned blockchains"
    - "formal specification and verification of smart contracts for azure blockchain"

Connected through hyperedge HE-6 (induced by source paper "attacking the defi ecosystem with flash loans for fun and profit"):
  with members:
    - "libra fair order matching for electronic financial exchanges"
    - "flash boys 2 0 frontrunning transaction reordering and consensus instability in decentralized exchanges"
    - "harvey a greybox fuzzer for smart contracts"
    - "contractfuzzer fuzzing smart contracts for vulnerability detection"
    - "bitcoin ng a scalable blockchain protocol"

Connected through hyperedge HE-7 (induced by source paper "characterizing eosio blockchain"):
  with members:
    - "evulhunter detecting fake transfer vulnerabilities for eosio s smart contracts at webassembly level"
    - "characterizing code clones in the ethereum smart contract ecosystem"
    - "contractfuzzer fuzzing smart contracts for vulnerability detection"
    - "bitcoin transaction graph analysis"
    - "deanonymisation of clients in bitcoin p2p network"

Connected through hyperedge HE-8 (induced by source paper "smacs smart contract access control service"):
  with members:
    - "online detection of effectively callback free objects with applications to smart contracts"
    - "sereum protecting existing smart contracts against re entrancy attacks"
    - "vandal a scalable security analysis framework for smart contracts"

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)