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: "an lsb data hiding technique using natural number decomposition"
  Abstract: In this paper, a novel data hiding technique is proposed, as an improvement over the Fibonacci LSB data-hiding technique proposed by Battisti et al. and the technique using prime number system. First we mathematically model and generalize our approach. Then we propose our novel technique, based on decomposition of a number (pixel-value) as sum of natural numbers. The particular representation generates a different set of (virtual) bit-planes altogether, suitable for embedding purposes. They not only allow one to embed secret message in higher bit- planes but also do it without much distortion and in a reliable and secured manner, guaranteeing efficient retrieval of secret message. Analysis indicates that image quality of the stego-image hidden by the technique using the natural number decomposition technique improves drastically against that using prime and Fibonacci decomposition techniques. Experimental results show that stego-image is visually indistinguishable from cover-image.

Connected through hyperedge HE-1 (induced by source paper "survey of operating systems for the iot environment"):
  with members:
    - "internet of things iot a vision architectural elements and future directions"
    - "implementation of a real time passenger information system"
    - "a semi distributed reputation based intrusion detection system for mobile adhoc networks"

Connected through hyperedge HE-2 (induced by source paper "multipath routing of fragmented data transfer in a smart grid environment"):
  with members:
    - "detection and prevention of botnets and malware in an enterprise network"
    - "ant colony based routing for mobile ad hoc networks towards improved quality of services"
    - "data hiding techniques using prime and natural numbers"

Connected through hyperedge HE-3 (induced by source paper "authentication systems in internet of things"):
  with members:
    - "ant colony based routing for mobile ad hoc networks towards improved quality of services"
    - "a multi factor security protocol for wireless payment secure web authentication using mobile devices"

Connected through hyperedge HE-4 (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"
    - "grid security and integration with minimal performance degradation"
    - "data hiding techniques using prime and natural numbers"
    - "a semi distributed reputation based intrusion detection system for mobile adhoc networks"
    - "steganography of voip streams"

Connected through hyperedge HE-5 (induced by source paper "steganalysis detecting lsb steganographic techniques"):
  with members:
    - "reversible and irreversible data hiding technique"
    - "a survey on various data hiding techniques and their comparative analysis"
    - "steganography and steganalysis different approaches"
    - "data hiding techniques using prime and natural numbers"
    - "an lsb data hiding technique using prime numbers"

Connected through hyperedge HE-6 (induced by source paper "reversible and irreversible data hiding technique"):
  with members:
    - "an lsb data hiding technique using prime numbers"
    - "hiding inside html and other source codes"

Connected through hyperedge HE-7 (induced by source paper "applicability of dukpt key management scheme to cloud wallet and other mobile payments"):
  with members:
    - "rism reputation based intrusion detection system for mobile ad hoc networks"

Connected through hyperedge HE-8 (induced by source paper "application layer intrusion detection with combination of explicit rule based and machine learning algorithms and deployment in cyber defence program"):
  with members:
    - "a new clustering approach for anomaly intrusion detection"

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)