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: "time protection the missing os abstraction"
  Abstract: Timing channels enable data leakage that threatens the security of computer systems, from cloud platforms to smartphones and browsers executing untrusted third-party code. Preventing unauthorised information flow is a core duty of the operating system, however, present OSes are unable to prevent timing channels. We argue that OSes must provide time protection in addition to the established memory protection. We examine the requirements of time protection, present a design and its implementation in the seL4 microkernel, and evaluate its efficacy as well as performance overhead on Arm and x86 processors.

Connected through hyperedge HE-1 (induced by source paper "specfuzz bringing spectre type vulnerabilities to the surface"):
  with members:
    - "context leakage free transient execution"
    - "specusym speculative symbolic execution for cache timing leak detection"
    - "spectre is here to stay an analysis of side channels and speculative execution"
    - "netspectre read arbitrary memory over network"
    - "safespec banishing the spectre of a meltdown with leakage free speculation"
    - "spectector principled detection of speculative information flows"
    - "spectre attacks exploiting speculative execution"
    - "you shall not bypass employing data dependencies to prevent bounds check bypass"

Connected through hyperedge HE-2 (induced by source paper "abstract interpretation under speculative execution"):
  with members:
    - "mitigating power side channels during compilation"
    - "eliminating timing side channel leaks using program repair"
    - "adversarial symbolic execution for detecting concurrency related cache timing leaks"
    - "spectre attacks exploiting speculative execution"
    - "canal a cache timing analysis framework via llvm transformation"
    - "modular verification of interrupt driven software"
    - "thread modular static analysis for relaxed memory models"
    - "flow sensitive composition of thread modular abstract interpretation"

Connected through hyperedge HE-3 (induced by source paper "binsec rel efficient relational symbolic execution for constant time at binary level"):
  with members:
    - "get rid of inline assembly through verification oriented lifting"
    - "symbolic verification of cache side channel freedom"
    - "eliminating timing side channel leaks using program repair"
    - "microwalk a framework for finding side channels in binaries"
    - "relational symbolic execution"
    - "a software approach to defeating side channels in last level caches"
    - "rigorous analysis of software countermeasures against cache attacks"

Connected through hyperedge HE-4 (induced by source paper "verifying that a compiler preserves concurrent value dependent information flow security"):
  with members:
    - "bridging the gap between programming languages and hardware weak memory models"

Connected through hyperedge HE-5 (induced by source paper "can we prove time protection"):
  with members:
    - "spectre attacks exploiting speculative execution"

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.OS(Operating Systems)