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: "discovering quantifying and displaying attacks"
  Abstract: In the design of software and cyber-physical systems, security is often#N#perceived as a qualitative need, but can only be attained quantitatively.#N#Especially when distributed components are involved, it is hard to predict and#N#confront all possible attacks. A main challenge in the development of complex#N#systems is therefore to discover attacks, quantify them to comprehend their#N#likelihood, and communicate them to non-experts for facilitating the decision#N#process. To address this three-sided challenge we propose a protection analysis#N#over the Quality Calculus that (i) computes all the sets of data required by an#N#attacker to reach a given location in a system, (ii) determines the cheapest#N#set of such attacks for a given notion of cost, and (iii) derives an attack#N#tree that displays the attacks graphically. The protection analysis is first#N#developed in a qualitative setting, and then extended to quantitative settings#N#following an approach applicable to a great many contexts. The quantitative#N#formulation is implemented as an optimisation problem encoded into#N#Satisfiability Modulo Theories, allowing us to deal with complex cost#N#structures. The usefulness of the framework is demonstrated on a national-scale#N#authentication system, studied through a Java implementation of the framework.

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)