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: "relating two standard notions of secrecy"
  Abstract: Two styles of definitions are usually considered to express that a security protocol preserves the confidentiality of a data s. Reach- ability-based secrecy means that s should never be disclosed while equi- valence-based secrecy states that two executions of a protocol with dis- tinct instances for s should be indistinguishable to an attacker. Although the second formulation ensures a higher level of security and is closer to cryptographic notions of secrecy, decidability results and automatic tools have mainly focused on the first definition so far. This paper initiates a systematic investigation of situations where syn- tactic secrecy entails strong secrecy. We show that in the passive case, reachability-based secrecy actually implies equivalence-based secrecy for signatures, symmetric and asymmetric encryption provided that the prim- itives are probabilistic. For active adversaries in the case of symmetric encryption, we provide sucient (and rather tight) conditions on the protocol for this implication to hold.

Connected through hyperedge HE-1 (induced by source paper "a type system for privacy properties technical report"):
  with members:
    - "partial order reduction for security protocols"

Connected through hyperedge HE-2 (induced by source paper "data minimisation in communication protocols a formal analysis framework and application to identity management"):
  with members:
    - "the identity crisis security privacy and usability issues in identity management"
    - "compiling and securing cryptographic protocols"

Connected through hyperedge HE-3 (induced by source paper "psi calculi a framework for mobile processes with nominal data and logic"):
  with members:
    - "a fully abstract symbolic semantics for psi calculi"
    - "formalising the pi calculus using nominal logic"

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)