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: "grid security and integration with minimal performance degradation"
  Abstract: Computational grids are believed to be the ultimate framework to meet the growing computational needs of the scientific community. Here, the processing power of geographically distributed resources working under different ownerships, having their own access policy, cost structure and the likes, is logically coupled to make them perform as a unified resource. The continuous increase of availability of high-bandwidth communication as well as powerful computers built of low-cost components further enhance chances of computational grids becoming a reality. However, the question of grid security remains one of the important open research issues. Here, we present some novel ideas about how to implement grid security, without appreciable performance degradation in grids. A suitable alternative to the computationally expensive encryption is suggested, which uses a key for message authentication. Methods of secure transfer and exchange of the required key(s) are also discussed.

Connected through hyperedge HE-1 (induced by source paper "synchronous relaying of sensor data"):
  with members:
    - "study of encryption and decryption of wave file in image formats"
    - "ant colony based routing for mobile ad hoc networks towards improved quality of services"
    - "sleep deprivation attack detection in wireless sensor network"
    - "data hiding techniques using prime and natural numbers"
    - "a semi distributed reputation based intrusion detection system for mobile adhoc networks"
    - "steganography of voip streams"
    - "an lsb data hiding technique using natural number decomposition"

Connected through hyperedge HE-2 (induced by source paper "increasing security in cloud environment"):
  with members:
    - "rism reputation based intrusion detection system for mobile ad hoc networks"
    - "detection and prevention of botnets and malware in an enterprise network"
    - "a paxos based state machine replication system for anomaly detection"
    - "a multi dimensional approach towards intrusion detection system"
    - "a hybrid approach towards intrusion detection based on artificial immune system and soft computing"
    - "a survey on security issues in cloud computing"
    - "a new trusted and collaborative agent based approach for ensuring cloud security"
    - "embedding secret data in html web page"

Connected through hyperedge HE-3 (induced by source paper "inter cloud data security strategies"):
  with members:
    - "rism reputation based intrusion detection system for mobile ad hoc networks"
    - "increasing security in cloud environment"
    - "a survey on security issues in cloud computing"
    - "a new trusted and collaborative agent based approach for ensuring cloud security"
    - "security scheme for distributed dos in mobile ad hoc networks"
    - "implementation of a cloud data server cds for providing secure service in e business"
    - "a semi distributed reputation based intrusion detection system for mobile adhoc networks"
    - "a brief history of the internet"

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)