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 "verifying public keys without trust how anonymity can guarantee data integrity"):
  Abstract: Despite the inroads that public-key cryptography has made on the web, the difficulty of key management has for the most part kept it out of the hands of the general public. With key-distribution software for PGP beginning to natively support the anonymizing service Tor, we describe a protocol to take advantage of this, allowing users and identity holders to detect malicious keyservers with an known and arbitrarily small probability of failure, allowing users to safely exchange public keys across the internet without the need for certificate authorities.

Includes members:
  Member "enhancing bitcoin security and performance with strong consistency via collective signing":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "surface a practical blockchain consensus algorithm for real world networks")
  Member "identifying and characterizing sybils in the tor network":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "how do tor users interact with onion services")
  Member "keeping authorities honest or bust with decentralized witness cosigning":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "que sera consensus simple asynchronous agreement with private coins and threshold logical clocks")

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)