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: "ghera a repository of android app vulnerability benchmarks"
  Abstract: Security of mobile apps affects the security of their users. This has fueled the development of techniques to automatically detect vulnerabilities in mobile apps and help developers secure their apps; specifically, in the context of Android platform due to openness and ubiquitousness of the platform. Despite a slew of research efforts in this space, there is no comprehensive repository of up-to-date and lean benchmarks that contain most of the known Android app vulnerabilities and, consequently, can be used to rigorously evaluate both existing and new vulnerability detection techniques and help developers learn about Android app vulnerabilities. In this paper, we describe Ghera, an open source repository of benchmarks that capture 25 known vulnerabilities in Android apps (as pairs of exploited/benign and exploiting/malicious apps). We also present desirable characteristics of vulnerability benchmarks and repositories that we uncovered while creating Ghera.

Connected through hyperedge HE-1 (induced by source paper "are free android app security analysis tools effective in detecting known vulnerabilities"):
  with members:
    - "do android taint analysis tools keep their promises"
    - "horndroid practical and sound static analysis of android applications by smt solving"
    - "an application package configuration approach to mitigating android ssl vulnerabilities"

Connected through hyperedge HE-2 (induced by source paper "sema extending and analyzing storyboards to develop secure android apps"):
  with members:
    - "web apis in android through the lens of security"
    - "are free android app security analysis tools effective in detecting known vulnerabilities"
    - "do android taint analysis tools keep their promises"

Connected through hyperedge HE-3 (induced by source paper "benchpress analyzing android app vulnerability benchmark suites"):
  with members:
    - "are free android app security analysis tools effective in detecting known vulnerabilities"
    - "do android taint analysis tools keep their promises"
    - "horndroid practical and sound static analysis of android applications by smt solving"
    - "beebs open benchmarks for energy measurements on embedded platforms"

Connected through hyperedge HE-4 (induced by source paper "sema a design methodology for building secure android apps"):
  with members:
    - "are free android app security analysis tools effective in detecting known vulnerabilities"
    - "do android taint analysis tools keep their promises"
    - "model driven development of complex software a research roadmap"

Connected through hyperedge HE-5 (induced by source paper "a benchmark of data loss bugs for android apps"):
  with members:
    - "verifying policy enforcers"
    - "policy enforcement with proactive libraries"
    - "healing data loss problems in android apps"

Connected through hyperedge HE-6 (induced by source paper "security code smells in android icc"):
  with members:
    - "an empirical study on android related vulnerabilities"
    - "adsplit separating smartphone advertising from applications"

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)