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: "quantitative information flow as safety and liveness hyperproperties"
  Abstract: We employ Clarkson and Schneider's "hyperproperties" to classify various verification problems of quantitative information flow. The results of this paper unify and extend the previous results on the hardness of checking and inferring quantitative information flow. In particular, we identify a subclass of liveness hyperproperties, which we call "k-observable hyperproperties", that can be checked relative to a reachability oracle via self composition.

Connected through hyperedge HE-1 (induced by source paper "quantitative aspects of programming languages and systems over the past 2 4 years and beyond"):
  with members:
    - "paws a tool for the analysis of weighted systems"
    - "divide and conquer variable set separation in hybrid systems reachability analysis"
    - "logical characterization of trace metrics"
    - "design and optimisation of the flyfast front end for attribute based coordination"
    - "language based abstractions for dynamical systems"
    - "limit your consumption finding bounds in average energy games"
    - "mela modelling in ecology with location attributes"
    - "logical characterization of bisimulation metrics"

Connected through hyperedge HE-2 (induced by source paper "hybrid statistical estimation of mutual information and its application to information flow"):
  with members:
    - "what s the over under probabilistic bounds on information leakage"
    - "a game theoretic approach to information flow control via protocol composition"
    - "information leakage games"
    - "on the compositionality of quantitative information flow"
    - "quantitative information flow for scheduler dependent systems"
    - "speeding up smt based quantitative program analysis"
    - "a scalable approximate model counter"

Connected through hyperedge HE-3 (induced by source paper "model checking quantitative hyperproperties"):
  with members:
    - "the density of linear time properties"
    - "datalair efficient block storage with plausible deniability against multi snapshot adversaries"
    - "plausible deniability for privacy preserving data synthesis"
    - "the complexity of counting models of linear time temporal logic"
    - "a temporal logic for hyperproperties"
    - "on bounding problems of quantitative information flow"

Connected through hyperedge HE-4 (induced by source paper "a monadic framework for relational verification applied to information security program equivalence and optimizations"):
  with members:
    - "proof relevant logical relations for name generation"
    - "hypercollecting semantics and its application to static analysis of information flow"
    - "lightdp towards automating differential privacy proofs"
    - "language integrated provenance"
    - "higher order approximate relational refinement types for mechanism design and differential privacy"
    - "the foundational cryptography framework"
    - "abstract effects and proof relevant logical relations"
    - "logical step indexed logical relations"

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)