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: "privacy constraints in regularized convex optimization"
  Abstract: This paper is withdrawn due to some errors, which are corrected in arXiv:0912.0071v4 [cs.LG].

Connected through hyperedge HE-1 (induced by source paper "utility privacy tradeoffs in databases an information theoretic approach"):
  with members:
    - "calibrating data to sensitivity in private data analysis"
    - "privacy against statistical inference"
    - "on privacy preserving histograms"
    - "discriminatory lossy source coding side information privacy"
    - "competitive privacy in the smart grid an information theoretic approach"
    - "on the relation between differential privacy and quantitative information flow"
    - "an information theoretic approach to privacy"
    - "secure source coding with a helper"

Connected through hyperedge HE-2 (induced by source paper "an information theoretic approach to privacy"):
  with members:
    - "on privacy preserving histograms"

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)