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: "timecrypt a scalable private time series data store"
  Abstract: We present TimeCrypt, an efficient and scalable system that augments time series data stores with encrypted data processing capabilities and features a new encryption-based access control scheme that is additively homomorphic. TimeCrypt is tailored for time series workloads, supports fast statistical queries over large volumes of encrypted time series data, and enables users to cryptographically restrict the scope of queries and data access based on pre-defined access policies. Our evaluation of TimeCrypt shows that its memory overhead and performance are competitive and close to operating on data in the clear (insecure). E.g., with data ingest at 2.4 million data points per second, we experience a slowdown of around 1.8% for both encrypted data ingest and statistical queries.

Connected through hyperedge HE-1 (induced by source paper "droplet decentralized authorization for iot data streams"):
  with members:
    - "towards blockchain based auditable storage and sharing of iot data"
    - "consensus in the age of blockchains"
    - "casper the friendly finality gadget"
    - "hijacking bitcoin routing attacks on cryptocurrencies"
    - "distributed authorization in vanadium"
    - "enhancing bitcoin security and performance with strong consistency via collective signing"
    - "bitcoin ng a scalable blockchain protocol"
    - "majority is not enough bitcoin mining is vulnerable"

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)