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: "google android a state of the art review of security mechanisms"
  Abstract: Google's Android is a comprehensive software framework for mobile communication devices (i.e., smartphones, PDAs). The Android framework includes an operating system, middleware and a set of key applications. The incorporation of integrated access services to the Internet on such mobile devices, however, increases their exposure to damages inflicted by various types of malware. This paper provides a comprehensive security assessment of the Android framework and the security mechanisms incorporated into it. A methodological qualitative risk analysis that we conducted identifies the high-risk threats to the framework and any potential danger to information or to the system resulting from vulnerabilities that have been uncovered and exploited. Our review of current academic and commercial solutions in the area of smartphone security yields a list of applied and recommended defense mechanisms for hardening mobile devices in general and the Android in particular. Lastly, we present five major (high-risk) threats to the Android framework and propose security solutions to mitigate them. We conclude by proposing a set of security mechanisms that should be explored and introduced into Android-powered devices.

Connected through hyperedge HE-1 (induced by source paper "static analysis for extracting permission checks of a large scale framework the challenges and solutions for analyzing android"):
  with members:
    - "quire lightweight provenance for smart phone operating systems"

Connected through hyperedge HE-2 (induced by source paper "automatically securing permission based software by reducing the attack surface an application to android"):
  with members:
    - "quire lightweight provenance for smart phone operating systems"

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)