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: "auditing australian senate ballots"
  Abstract: We explain why the Australian Electoral Commission should perform an audit of the paper Senate ballots against the published preference data files. We suggest four different post-election audit methods appropriate for Australian Senate elections. We have developed prototype code for all of them and tested it on preference data from the 2016 election.

Connected through hyperedge HE-1 (induced by source paper "a trustworthy electronic voting system for australian federal elections"):
  with members:
    - "public evidence from secret ballots"
    - "trust implications of ddos protection in online elections"
    - "secure and verifiable electronic voting in practice the use of vvote in the victorian state election"

Connected through hyperedge HE-2 (induced by source paper "public evidence from secret ballots"):
  with members:
    - "efficient computation of exact irv margins"
    - "diffsum a simple post election risk limiting audit"
    - "end to end verifiability"
    - "the new south wales ivote system security failures and verification flaws in a live online election"
    - "vvote a verifiable voting system"

Connected through hyperedge HE-3 (induced by source paper "towards computing victory margins in stv elections"):
  with members:
    - "algorithms for destructive shift bribery"
    - "the computational impact of partial votes on strategic voting"
    - "how hard is bribery in elections"
    - "how many candidates are needed to make elections hard to manipulate"

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)