human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "the key to intelligent transportation identity and credential management in vehicular communication systems"):
  Abstract: Vehicular communication (VC) systems will greatly enhance intelligent transportation systems. But their security and the protection of their users' privacy are a prerequisite for deployment. Efforts in industry and academia brought forth a multitude of diverse proposals. These have now converged to a common view, notably on the design of a security infrastructure, a vehicular public-key infrastructure (VPKI) that shall enable secure conditionally anonymous VC. Standardization efforts and industry readiness to adopt this approach hint at its maturity. However, there are several open questions remaining, and it is paramount to have conclusive answers before deployment. In this article, we distill and critically survey the state of the art for identity and credential management in VC systems, and we sketch a road map for addressing a set of critical remaining security and privacy challenges.

Includes members:
  Member "towards deploying a scalable robust vehicular identity and credential management infrastructure":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "resilient collaborative privacy for location based services")
  Member "vespa vehicular security and privacy preserving architecture":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "resilient privacy protection for location based services through decentralization")
  Member "on the road reflections on the security of vehicular communication systems":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "scaling pseudonymous authentication for large mobile systems")
  Member "impact of vehicular communications security on transportation safety":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "resilient collaborative privacy for location based services")
  Member "secure vehicular communication systems design and architecture":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "scaling pseudonymous authentication for large mobile systems")

Question: Please tell me which class the source paper 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)