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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>CNN-KPCA: A hybrid Convolutional Neural Network with Kernel Principal Component Analysis for Intrusion Detection System for the Internet of Things Environments</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Joseph Bamidele Awotunde</string-name>
          <email>awotunde.jb@unilorin.edu.ng</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Ranjit Panigrahi</string-name>
          <email>ranjit.panigrahi@gmail.com</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Biswajit Brahma</string-name>
          <email>biswajit.Brahma@gmail.com</email>
          <xref ref-type="aff" rid="aff3">3</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Akash Kumar Bhoi</string-name>
          <email>akashkrbhoi@gmail.com</email>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Department of Computer Applications, Sikkim Manipal Institute of Technology, Sikkim Manipal University</institution>
          ,
          <addr-line>Sikkim</addr-line>
          ,
          <country country="IN">India</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Department of Computer Science, University of Ilorin</institution>
          ,
          <addr-line>Ilorin</addr-line>
          ,
          <country country="NG">Nigeria</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>Directorate of Research, Sikkim Manipal University</institution>
          ,
          <addr-line>Gangtok, Sikkim</addr-line>
          ,
          <country country="IN">India</country>
        </aff>
        <aff id="aff3">
          <label>3</label>
          <institution>McKesson Corporation</institution>
          ,
          <addr-line>1 Post St, San Francisco, CA 94104</addr-line>
          ,
          <country country="US">USA</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2020</year>
      </pub-date>
      <volume>8</volume>
      <issue>1</issue>
      <fpage>98</fpage>
      <lpage>113</lpage>
      <abstract>
        <p>The combination of several Machine Learning and Deep Learning techniques has been spurred by the need to address security breaches inside an Internet of Things (IoT) focused environment. This research presents a novel way to solve the challenge of classifying normal and abnormal attacks on the Domain Name System (DNS) protocol. The proposed method involves the use of a hybrid model that combines Convolutional Neural Networks (CNN) with Principal Component Analysis (PCA). The methodology begins by transforming nominal features into numerical data as part of the preprocessing stage. The quantitative data is subsequently subjected to PCA in order to identify features, reducing the dimensions of the dataset by separating the most important properties. Following this, the data is inputted into the CNN with the objective of detecting and categorizing anomalous behaviors inside the IoT ecosystem. The effectiveness of the hybrid model was assessed by employing the IoTID20 dataset. The model exhibited exceptional performance in terms of accuracy, recall, F-Score, precision, and ROC metrics, surpassing those of existing detection methods. Significantly, the suggested framework not only improves security measures but also tackles privacy concerns and strengthens the maintainability of IoT-based systems.</p>
      </abstract>
      <kwd-group>
        <kwd>Machine learning</kwd>
        <kwd>Deep learning</kwd>
        <kwd>Principal component analysis</kwd>
        <kwd>Convolutional neural network</kwd>
        <kwd>Intrusion detection 1</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        The eventual convergence of cutting-edge sensor technology and the Internet of Things (IoT),
quickly infiltrating human existence, is unavoidable. The number of linked things on the Internet
will have surpassed 50 billion by 2020 [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ], [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ]. Data Streams are usually dynamic, such as in
timeseries format, and their memory consumption and processing time are constrained by hardware
and database server limits [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. Because they use centralized and broadened operating systems,
IT infrastructure, and applications, IoT-based systems are defenceless against traditional threats.
On the other hand, traditional cloud computing risks face new security concerns due to several
technological advancements that could lead to new types of misuse [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. Network Intrusion
Detection Systems (IDSs) are now essential for restoring network security, especially for
IoTbased systems [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]–[
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]. Because of the complexity and heterogeneity of these systems, it isn't easy
to find a haven for them from cyber-attacks [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]. Furthermore, having different types of operators
necessitates varying levels of protection.
      </p>
      <p>
        The loss of control over the infrastructure used by Cloud customers is one of the most serious
issues they face [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]. High missing and noisy perceptual data contribute to the imbalance trait in
IoT-based systems. Because the calculation capabilities of IoT capture devices and sensors are
0000-0002-1020-4432 (J.B. Awotunde); 0000-0001-6728-5977 (R. Panigrahi); 0000-0003-2759-3224 (A.K. Bhoi)
© 2023 Copyright for this paper by its authors.
      </p>
      <p>Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).</p>
      <p>
        CEUR Workshop Proceedings (CEUR-WS.org)
limited, any categorization for such data should be updated in on-the-fly response time. The IoT
security issues are not hidden from any organization, and their importance has been taken
seriously in various organizations [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]. In recent years, Artificial Intelligence (AI) has been used to
professionally and accurately handling security in IoT-based systems. The AI techniques help fill
the gaps of fighting against intruders that attack information in IoT-based systems for their gains,
thus significantly increasing the stakeholders' trust in IoT systems. IoT-based devices and sensors
operate in hostile environments, where physical layer fraud is a real possibility.
      </p>
      <p>
        A distributed denial of service (DDoS) attack, which sends enormous amounts of data by
consuming bandwidth access, is the most serious breach [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ], [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ]. Over a thousand botnets are
causing havoc on legitimate websites such as Amazon, eBay, Netflix, and even government
agencies. AI is a data-driven technique in which the first step is to grasp the data. Unique attack
behaviours are represented by several types of data, such as host activities and network activity.
Network traffic indicates network behaviour, whereas server logs describe host behaviour, and
numerous types of attacks exist, each with its own setup. As a result, selecting appropriate data
sources to detect various risks based on the threat's characteristics is crucial. The DoS attack has
the ability of sending multiple packets within a shortest time, and this is one of their key
characteristics, thus the flow data is suitable for identifying DoS attacks [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ], [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ].
      </p>
      <p>
        A secret channel is ideal for session data detection since it contains a data-leaking transaction
between two IP addresses. Hence, advancements in deep learning algorithms can aid in the
detection of specific network patterns [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ], [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ]. Therefore, this study proposes a CNN model
with PSO to optimize a flexible and secure architecture for safeguarding large-scale IoT networks.
The model was greatly enhanced by adding a deep learning algorithm to identify emerging
vulnerabilities to the IoT network to detect anomalies. This paper has the following
contributions:
• To detect intruders in an IoT environment, the team developed an advanced Deep
      </p>
      <p>
        Learning model termed the hybrid CCN-KPCA[
        <xref ref-type="bibr" rid="ref15">15</xref>
        ] technique.
• The effectiveness of the system underwent evaluation using an IoT-based network
dataset generated in 2020, presenting a significant challenge in establishing a strong
framework.
• A thorough performance comparison was executed with a recent research study utilizing
the same dataset, considering various performance metrics.
      </p>
    </sec>
    <sec id="sec-2">
      <title>2. Related Works</title>
      <p>
        With the exponential growth of IoT devices protecting critical resources and associated services
is becoming a challenging task for the service providers [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ]. Malware and related attacks are the
most common threats in IoT networks. Hackers utilise a range of tactics to detect and control the
behaviour of vulnerable resources, including the entire computing environment. Traditional
cyber-threat approaches such as security protocols, cryptography [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ], access controls were
shown to be ineffectual and no longer appropriate for delivering effective critical infrastructure
protection [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ], [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ]. Therefore, efforts has been given to design stat of the art Intrusion Detection
Systems (IDS) in a variety of computing environments [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ]–[
        <xref ref-type="bibr" rid="ref25">25</xref>
        ]. The IoT has become a vital part
of today's data and information transmission machinery, necessitating global network security
[
        <xref ref-type="bibr" rid="ref26">26</xref>
        ]. The traditional Machine Learning (ML) and Deep Learning (DL) models are critical in the
development of an intelligent system in cybersecurity based on IoT. As a result of IoT devices,
most businesses and organisations have undergone digital revolutions. However, this has
generated new problems and vulnerabilities that can be exploited quickly once hackers become
aware of them. Qaddoura et. al [
        <xref ref-type="bibr" rid="ref27">27</xref>
        ] proposed an IDS using multistage classification approach for
IoT framework. During the training procedure, the network data has been oversampled with the
use of Synthetic Minority Oversampling Technique and Support Vector Machine. The main
technique of this method is the use of Single Hidden Layer Feed-Forward Neural Network (SLFN)
for network detection. Multistage IDS has also been explored by Anthi et al [
        <xref ref-type="bibr" rid="ref28">28</xref>
        ]. The IDS consists
of three layers a stage to classify the malicious and benign instances and the last layer designed
to detect attack types. The layered approach successfully detects DoS and man in the middle
attacks. In a similar node a two layers classification approach using Naïve Bayes and k-Nearest
Neighbour has been used to keep track of User to Root (U2R) and Remote to Local (R2L) attacks
[
        <xref ref-type="bibr" rid="ref29">29</xref>
        ]. Similarly, to choose the aspects of malicious attack behaviours, a feature selection strategy
[
        <xref ref-type="bibr" rid="ref30">30</xref>
        ] was presented, and the system provided an appropriate means of defending enterprises
from cybercrime. For the detection of botnet attack at the host and network levels, ML algorithms
have been proved effective in the IoT-based environment [
        <xref ref-type="bibr" rid="ref30">30</xref>
        ]. Similarly, host level attacks are
also detected marvellously using deep leaning models [
        <xref ref-type="bibr" rid="ref31">31</xref>
        ]. To detect intrusion and improve the
prior model, reference [
        <xref ref-type="bibr" rid="ref32">32</xref>
        ] proposed an intelligent mechanism
model based on a
decisionmaking process; they constructed a recurrent neural network (RNN). Reference [
        <xref ref-type="bibr" rid="ref32">32</xref>
        ] used
autoencoder for feature extraction to select revenant features before using CNN for classification
the dataset for any possible attacks.
      </p>
      <p>
        Recently, an intelligent IDS has been proposed for IoT based environment, where the detector
is able to protect all the devices connected directly to its interface[
        <xref ref-type="bibr" rid="ref33">33</xref>
        ]. The Passban detector
successfully detect SSH brute force, HTTP, port scanning and SYN flood attacks. To boost feature
extraction across layers, a CNN was employed to identify infiltration [
        <xref ref-type="bibr" rid="ref34">34</xref>
        ], and feature fusion
techniques were applied to acquire the whole attack characteristics. Reference [
        <xref ref-type="bibr" rid="ref35">35</xref>
        ] developed a
solution to protect IoT in healthcare by managing traffic and brightening the environment.
Security measures for IoT systems have also been devised, as mentioned in [
        <xref ref-type="bibr" rid="ref36">36</xref>
        ] and [
        <xref ref-type="bibr" rid="ref37">37</xref>
        ]. In a
similar node, Ullah et al [38] proposed a new botnet based IoT dataset to test various flow based
intrusion detection systems. The logistic regression on the new botnet dataset shows 96%
detection accuracy on 20 attack features in the training model.
      </p>
      <p>The reviewed works have shown that deep learning models can significantly improve the
accuracy and efficiency of IDSs in an IoT-based environment, thus retaining a low false alarm rate.
Hence, the study proposes a hybrid CNN-enabled PCA feature extraction and classification of
anomaly trends detection in IoT-based systems. The PCA methods reduce the feature to minimize
and useful one, thereby increasing the accuracy of the proposed model for detecting an intruder
on an IoT-based system.</p>
    </sec>
    <sec id="sec-3">
      <title>3. The Method</title>
      <p>
        The approaches that are employed in accordance with the KPCA-CNN [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ] framework consist of
three primary stages: (i) preprocessing, (ii) feature selection, and (iii) classification. During the
preprocessing phase, nominal qualities are initially transformed into numeric features in order
to streamline later processing steps. The process of feature selection entails employing Kernel
Principal Component Analysis (KPCA) to discover significant attributes within each class, hence
lowering the dimensionality of the vector. The CNN model is utilized for the purpose of classifying
events inside the IoTID20 dataset, with a specific focus on identifying potential attacks.
The data preparation stage primarily covers two main ways. First and foremost, the process of
data conversion entails the translation of nominal properties into numerical features in order to
facilitate subsequent processing. Additionally, the objective of data normalization is to address
the significant variability of attributes by constraining values to a rational range. The normalizing
process can be theoretically defined by equation (1) through the utilization of the
minimummaximum scaling method.
      </p>
      <p>
        =

 − 
( ) − 
( )
( )
(1)
where dataset feature value is indicated by  , and it is in the range of [
        <xref ref-type="bibr" rid="ref1">0, 1</xref>
        ].
features, particularly in complex structures, an alternate method such as KPCA is required in
order to successfully overcome this constraint.
      </p>
      <p>A convolution kernel is applied within the convolution layer in order to progress the learning
and classification process. This results in the generation of a new feature graph that is comprised
of numerous interconnected feature graphs. These interconnected feature graphs are utilized as
an input signal for distinct convolution cores. Convolving many feature graphs together produces
each output feature graph, which in turn contributes to the formation of another output layer
[39]. The computation is carried out as follows within the convolution layer:
   = 
   −1x   +</p>
      <p>(2)
where    represents the  feature and the layer map  ,     represents the convolutional kernel
function,  represents the activation function, and both    and   represents bias parameter and
the input feature graph respectively.</p>
    </sec>
    <sec id="sec-4">
      <title>4. The dataset</title>
      <p>The newly developed IoTID20 attack dataset was generated in the year 2020 [40]. The dataset
included 80 features from PCAP files, with two basic class label attacks and normal. Table 1 lists
all of the IoTID20 dataset assaults, whereas Table 2 lists the number of characteristics for each
class label.</p>
    </sec>
    <sec id="sec-5">
      <title>5. Results and Discussion</title>
      <p>The research employed actual data obtained from an Internet of Things (IoT) cybersecurity
network. The CNN-KPCA model was utilized to categorize different types of threats present in the
network dataset. The utilization of the KCPA model yielded notable enhancements in feature
extraction, leading to substantial gains in both classification performance and model correctness.
Significantly, the procedure of feature selection successfully decreased the total number of
features from 81 to 19, identifying these specific features as the most essential components for
detecting intrusions inside the dataset.</p>
      <p>The dataset consisted of a total of 625,783 instances. To provide a comprehensive analysis, the
data was divided into two partitions: 80 percent (500,627 instances) were allocated for training
purposes, while the remaining 20 percent (125,155 instances) were reserved for testing. This
division was necessary due to the large number of examples in the dataset. Table 3 presents a
wide array of measures utilized to assess the performance of the suggested model.</p>
      <p>The suggested model produced the best outcomes when tested against the IoT-based dataset
utilized for performance data from the network to detect infiltration. The overall effectiveness of
the suggested CNN-KPCA model is shown in Figure 2. The IDS model performance is evaluated in
Table 3 using two classes of attacks and the baseline condition; the CNN-KPCA model performs
better, with 99.35% accuracy, 99.71% sensitivity, 91.26% specificity, 98.57 precision, and
99.21% F1-score, respectively.</p>
      <p>
        Recent research investigations that used the same dataset as the CNN-KPCA model were
compared with it, particularly the research that produced the dataset used for evaluation. Several
ML-based models, including Linear Discriminant Analysis (LDA), Decision with Random Forest,
Support Vector Machine (SVM), and Gaussian Nave Bays (NB) from the IoT-based platform, were
utilized in the baseline analysis on the dataset for the identification of intrusions [39]. Another
important study by authors in [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ] used CNN, LSTM, and CNN-LSTM on the same dataset and
minimized the features from the network dataset from 81 to 21 revenant features using the
particle swarm optimization approach (PSO). In order to further increase the accuracy of
intrusion detection on the dataset, this study suggested CNN-KPCA. In order to handle the
unbalanced data and minimize the number of characteristics from 81 to 19, the KCPA model was
employed. This helped the suggested model accurately identify attackers on the IoT-based
platform.
      </p>
      <p>F1-Score
37.00%</p>
      <p>40.00%
Precision</p>
      <p>From Figure 3, the results show that the CNN-KPCA framework performed better and yielded
a better detection accuracy using various metrics with other ML models.</p>
    </sec>
    <sec id="sec-6">
      <title>6. Conclusion</title>
      <p>The proliferation of ransomware and malicious botnets in the realm of IoT systems poses a
substantial risk to the privacy of users. These threats have the ability to intentionally focus on IoT
systems in various industries, potentially resulting in significant harm that could affect the assets
of several clients, particularly in vital domains such as healthcare, banking, smart cities, and
others. The mitigation of these hazards requires the implementation of strong network intrusion
detection systems (NIDSs) that are capable of efficiently detecting and mitigating online attacks.
These systems play a crucial role in ensuring the security of networks. This study presents a novel
approach that combines DL techniques to develop a model capable of detecting intrusions in
networks based on the IoT. The research use the KPCA model as a means to identify key
components that are vital for the detection of unauthorized individuals within IoT network
platforms. Following this, a CNN is utilized to categorize the dataset based on the IoT, so assessing
the effectiveness of the model proposed. The results of the performance evaluations demonstrate
that the proposed model exhibits superior performance compared to currently employed
approaches, with a remarkable accuracy rate of 99.35%. This demonstrates a significant
improvement of 1.35% in accuracy when compared to the nearest CCN-LSTM models that utilized
the identical dataset.</p>
      <p>Future study should aim to investigate contemporary classification approaches and design
concepts in order to evaluate the robustness of IDS against a wide range of threats. The
exploitation of conventional deep learning methods by intruders frequently results in notable
instances of false alarms. This emphasizes the necessity for adaptive strategies to effectively
address these difficulties.</p>
      <p>(CISTI), 2018, pp. 1–7.</p>
    </sec>
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