<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving and Interchange DTD v1.0 20120330//EN" "JATS-archivearticle1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>International Journal
of Information Management 43 (2018) 248-260. URL: https://doi.org/10.1016/j.ijinfomgt.
2018.08.008. doi:10.1016/j.ijinfomgt.2018.08.008.
[26] H. Beheshti</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="doi">10.1109/icmtma.2019.00135</article-id>
      <title-group>
        <article-title>Qualitative and Quantitative Characteristics Analysis for Information Security Risk Assessment in E-Commerce Systems</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Aleksandr Gozhyj</string-name>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Irina Kalinina</string-name>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Victoria Vysotska</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Svitlana Sachenko</string-name>
          <xref ref-type="aff" rid="aff3">3</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Roman Kovalchuk</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Hetman Petro Sahaidachnyi National Army Academy</institution>
          ,
          <addr-line>Heroes of Maidan street, 32, Lviv, 79012</addr-line>
          ,
          <country country="UA">Ukraine</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Lviv Polytechnic National University</institution>
          ,
          <addr-line>S,.Bandera street, 12, Lviv, 79013</addr-line>
          ,
          <country country="UA">Ukraine</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>Petro Mohyla Black Sea National University</institution>
          ,
          <addr-line>68 Desantnykiv, 10, 54003, Mykolaiv</addr-line>
          ,
          <country country="UA">Ukraine</country>
        </aff>
        <aff id="aff3">
          <label>3</label>
          <institution>Ternopil National Economic University</institution>
          ,
          <addr-line>Lvivska Street, 11, Ternopil, 46004</addr-line>
          ,
          <country country="UA">Ukraine</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2020</year>
      </pub-date>
      <volume>2604</volume>
      <fpage>0000</fpage>
      <lpage>0002</lpage>
      <abstract>
        <p>The choice of security profile in e-commerce systems depends on the results of the analysis of quantitative and qualitative characteristics of information security risk assessment. The article analyses the concept of information in the aspect of property rights object and investigates threats to information security in electronic commerce systems based on systematic attacks series frequency analysis on the system.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Information Security</kwd>
        <kwd>E-Commerce System</kwd>
        <kwd>Risk Assessment</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        Considering information as an object of protection, it should note that information is the result
of reflection and processing in the human consciousness of the diversity of the surrounding
world [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. Not only has a secret information needed a protection [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ]. Modifying unclassified
data can lead to leakage of classified information [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. The destruction or disappearance of data
that has accumulated with great dificulty can cause them to be lost. Depending on the scope of
a particular data processing system, the loss or leakage of confidential information can lead to a
variety of important consequences: from innocent jokes to the dramatic economic and political
consequences. In particular, common are the crimes in automated systems that serve banking
and trading structures.
      </p>
      <p>Therefore, it is very important to solve the problems of creating, using and evaluating the
efectiveness of information security systems (GIS) for the designed and existing electronic
commerce systems (ECS).</p>
    </sec>
    <sec id="sec-2">
      <title>2. Related Works Review</title>
      <p>
        Considering the importance of the information systems protection the following specific feature
should be taken into account [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]:
• Incompleteness and uncertainty of initial information on the composition of IP and
specific threats;
• Multi-criterion of the task, related to the need to account for a large number of indicators
(requirements) of GIS;
• Availability of quantitative and qualitative indicators that must be taken into account
when solving the tasks of KIC development and implementation;
• Impossibility of applying classical optimization methods.
      </p>
      <p>
        The model developed shall meet the following requirements [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ]:
• Used as: A Guide to Creating a GIS; Methods of formation of indicators and requirements
for GIS; Tool (methodology) for GIS assessment; GIS models for research (state matrix)
[
        <xref ref-type="bibr" rid="ref6">6</xref>
        ];
• Have properties: Versatility; Complexity; Easy to use; Clarity; Practical orientation; Being
self-educated (ability to increase knowledge); Operate in conditions of high uncertainty
of the initial information [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ];
• Allow: Establish a relationship between indicators (requirements); Set diferent levels of
protection; To receive quantitative estimates; Monitor the status of GIS; Apply diferent
assessment techniques; Respond promptly to changes in operating conditions; To unite
the eforts of diferent specialists with a single plan [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ].
      </p>
      <p>The value of information is a criterion when making any decision to protect it. Although
many diferent attempts have made to formalize this process using information theory and
decision analysis methods, the assessment process remains highly subjective. To evaluate, it
is necessary to divide the information into categories not only according to its value but also
according to its importance. The following is the distribution of information by importance [9]:
• Vital, irreplaceable information, the availability of which is necessary for the functioning
of the organization;
• Important information - information that can be replaced or restored, but the recovery
process is very dificult and costly;
• Useful information - information that is dificult to retrieve, but an organization can
function efectively without it;
• Irrelevant information - information that the organization no longer needs.</p>
      <p>In practice, attributing information to one of these categories is quite a challenge, since the
same information can used by many organizational units, each of which can be assigned to
diferent categories of importance. The importance category, as well as the value of
information, subsequently changes and depends on the attitude of diferent groups of consumers and
potential violators [10]. There are definitions of groups of persons involved in the processing of
information: the holder is the organization or the person who owns the information; source
the organization or person supplying the information; the ofender is a person or organization
who unlawfully seeks information. The attitude of these groups to the significance of the same
information may be diferent [11]. Example:
• Important online information, such as a list of current week orders and production
schedules, can be of high value to the user, while low to the source or ofender;
• Personal information, such as medical information, is of much greater value to the source
(the person concerned) than to its user or ofender [12];
• The information used by management to develop and make decisions, such as market
prospects, may be much more valuable to the ofender than to the source or holder who
has already completed the analysis of the data [13].</p>
      <p>These categories of importance are noteworthy and can applied to any information. This is
also consistent with the existing principle of the distribution of information by level of secrecy.
A level of secrecy is an administrative or legislative measure adequate to the extent of a person’s
liability for the leakage or loss of specific classified information, which is regulated by a special
document taking into account public, military, strategic, commercial, service or private interests.
Such information may be state, military, commercial, oficial or personal secret [ 14]. Practice
shows that not only secret information is protected. Unauthorized information subject to
unauthorized changes (such as modifications to management commands) may result in leakage
or loss of classified information associated with it, as well as failure to perform automated system
assignments due to erroneous data that may not detected by the system user [15]. The total
amount or statistics of non-classified data may be secret as a result. Similarly, aggregate data of
one level of secrecy may generally be information of higher secrecy. Functional delimitation of
access to information is widely used to protect against such situations. The equal importance,
the information processed by the system is shared according to the functional responsibilities
and authority of the users. Until recently, information security in automated systems (AUs) is
interpreted solely as a risk of unauthorized receipt of information throughout the processing and
storage of the AUs. Today, information security is also interpreted as security for actions that
use information [16]. The fundamental diferences of the extended interpretation, unlike the
traditional one, are very important as computer technology is increasingly used for automated
management of information systems and processes in which unauthorized changes to planned
algorithms and technologies can have serious consequences. Historically, a traditional property
object is a tangible object [17]. Information is not a material object, information is knowledge,
that is, the reflection of reality in the mind of man (and the true or false representation is not
essential, it is important that it is in the mind). In the future, information can translated into
tangible objects of the world. As an intangible object, information is inextricably linked to the
material medium [18]. This is the human brain or the alienated material, such as a book, floppy
disk, and other types of “memory” (computer memory). From a philosophical point of view, it is
possible to speak of information as an abstract substance existing in itself, but for us neither
storing nor transmitting information without a tangible medium is impossible [19].</p>
      <p>Risk analysis involves the study and systematization of threats to ECS, defining the
requirements for security tools for information systems [20, 21]. The analysis clarifies the permissible
residual risks and costs of information security measures, and then concludes on the permissible
residual risk levels and the feasibility of applying specific security options.</p>
      <p>Besides many recent references were dedicated by information security systems issues.</p>
      <p>
        In the Reference [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ] the complementary ISRA and MCDM methods are explored that could be
used as a basis to create a new hybrid model for more eficient evaluation of critical IT solutions
in information security(IS).
      </p>
      <p>
        Authors of the Reference [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] are solving a problem of weighting the risk factors that lead to
diferent risk values. The proposed metrics are classified and aggregated providing a unique
risk metric.
      </p>
      <p>
        The Reference [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ] presents the qualitative and quantitative depictions of ECSs from a complex
systems perspective, that provides a brand new idea of how to address the current issues of
information security in ECS.
      </p>
      <p>The Reference [22] present a Goal-driven Software Development Risk Management Model
(GSRM) and its explicit integration into the requirements engineering phase as well as an
empirical investigation result of applying GSRM into a project.</p>
      <p>The Reference [23] describes the impact of criminal activities based on the nature of the
crime, the victims of cybercrime in Internet. Authors proposed to utilize Fuzzy Inference Model
(FIS) to produce risk assessment result based on the four risk factors in particular, vulnerability,
threat, likelihood and impact as well as specify the range of risks and try to solve such issues.</p>
      <p>Based on the hierarchical structure of e-commerce security system, the Reference [24] analyses
the security requirements for e-commerce security and proposes a quantitative e-commerce
risk assessment model based on cloud computing.</p>
      <p>Authors of the Reference [25] designed a model that integrates fault tree analysis, decision
theory and fuzzy theory to determine the current causes of cyberattack prevention failures
and the vulnerability of a given cybersecurity system. The model was applied to evaluate the
cybersecurity risks caused by attacks on a website as well as assess the possible consequences
of such attacks.</p>
      <p>In the Reference [26] a model, based on the opinions of e-commerce security experts, is
designed and implemented by using fuzzy expert systems and MATLAB. A case study is
conducted to validate the efectiveness of this model.</p>
      <p>In the Reference [27] the data security in the systems of control of passenger flows in Smart
City is investigated. The Reference [28] is dedicated by the analysis of DDOS attacks features
on the basic machine learning. The Reference [29] describes the measurement instrument for
information technology risk assessment towards a risk management strategy.</p>
      <p>The Reference [30] explores the internal and external organizational factors and characteristics
of information security for afecting the e-commerce systems.</p>
      <p>The Reference [31] investigates the evaluation system of E-commerce specialty based on
TOPSIS and analytic hierarchy process.</p>
    </sec>
    <sec id="sec-3">
      <title>3. Proposed Methods and Materials</title>
      <p>When solving many theoretical and engineering problems, it is often necessary to know the
likelihood of a certain number of events occurring in a series. If the risk tests that form a
series are considered to independent, then we can make the necessary predictions using the
developed hypergeometric law. Consider this a simple example. Let 
insignificant threats, and each of the events occurred at a certain interval of   times
list of informational security threats, including  dangerous with serious consequences and 
events be taken from the
 = 1, , 
=  + ,</p>
      <p>= ∑  
probabilities of the occurrence of a particular event remain unchanged and are, respectively,
 /</p>
      <p>and  / .</p>
      <p>A probabilistic threat experiment that operates with the efects of mutually independent
trials, in each of which threat events retain their unconditional probabilities, is called repeated
sampling. In the implementation of the second scheme, the completed events are considered
to non-recurring. The probability of an event occurring in each subsequent trial depends on
the results of the previous tests. Thus, we are dealing with dependent tests, and the probability
of the result of each test is conditional. An experiment that runs on a sequence of dependent
tests, each of which results in conditional probabilities, is called a non-repetitive (or non-return)
sample. The real probabilistic threat experiment can carried out either by repeated or repeated
sampling [26].</p>
      <p>Let the event  ′ be that the threat of informational security 
more than  times. Then the probability   ( ≤  ≤  ) of this event is
will appear at least  and not
Graphically, the number of additives that need to be calculated can represented as follows

 =

 =
(Fig. 1):</p>
      <p>If the number of terms corresponding to the values of x from a to b is much greater than the
total number of terms corresponding to the values of  from 0 to  − 1 and from  − 1 to  , then
it is more convenient to summarize the probabilities for these two sequences. In this case, we
obtain the probability of the opposite event  ′ ∶  ( ′ ) = ∑ −=10
Now we calculate the required probability by the formula</p>
      <p>− − ∑ = +1</p>
      <p>− .
′
 −1
 =0
  ( ≤  ≤  ) = 1 −  (  ) = 1 − ∑   

  − −

∑   

Graphically, this approach can interpreted as follows (Fig. 2):
 


some unit of threat A will meet at least a times. Here
  ( ≥  ) = ∑   

If the value of a is small, it is advisable to use the expression
  ( ≥  ) = 1 − ∑   

which is a partial case of formula (3).
(3)
(4)
(5)
In the case when  = 1 , we have
  (1 ≤  ≤  ) = 1 −  0  
0  = 1 −   .
summing the probabilities in which the event appears 0, 1, 2, ...,  times:</p>
      <p>The probability of occurrence of event  no more than  b times is also determined by
  ( ≤  ) = ∑   


If the value of  is close to  , then this probability should calculated by the formula:
  ( ≤  ) = 1 − ∑   

which is also a partial case of formula (8).
systems in e-commerce systems, there is a constant need to determine the amount of potential
threats needed to ensure that information and financial transactions are securely assigned. To
do this, let’s first transform the formula</p>
      <p>(1 ≤  ≤  ) = 1 −   = 1 − (1 −  )
by the way (1 −  ) = 1 −   (1 ≤</p>
      <p>≤  ).</p>
      <p>We prologarify both parts of equality and after simple transformations we obtain
 =
 [1 −   (1 ≤  ≤  )]
 (1 −  )
,
where  indicates the required sample size.</p>
      <p>The hypergeometric law can applied only to finite general populations, the volume of which
is known. Since in security problems the volume of the general set of attacks is usually not a
predictable finite value, the application of this law to predict the results of experiments in unique
samples is unrealistic. However, under certain conditions, the hypergeometric probability is well
approximated by the binomial probability. Therefore, without fear of violating the mathematical
rigor, we will calculate the probabilities of occurrence of event  exactly  times in our unique
sample as if it were a re-sample. In other words, we apply binomial law to unique samples.</p>
      <p>We will consider the data of  attacks as  series or samples, each of which consists of 
independent tests. The event  can appear  times in each series ( = 0, 1, 2, ..., 
).It is easy
to notice that there are groups of series in which  appears 
= 0, 1, 2, ..., 
that the relative frequency of event  is exactly  times in one series is determined by the ratio
  ( ) =   / where</p>
      <p>is the number of series in which event  appears exactly  times.</p>
      <p>The a priori probability of occurrence of event  in one random series is equal to
times. It follows
and therefore,
 ≈
∑</p>
      <p>≈ 1 −
 
 
,
.</p>
      <p>(9)
(10)
(11)
(12)
(13)
tionality  .
exactly  times. Because</p>
      <p>In the obtained theoretical distribution, each value of  is correlated not by its probability,
but by some theoretically expected number of series (samples)   , in which event  appears

  =   ( ) =   

it is not dificult to notice that the values</p>
      <p>and   ( ) are related by coeficient of
propor</p>
      <p>Number of occurrences of the event 
Empirical frequencies of sampling  
0
0
1
1
2
4
3
15
4
33
5
27
6
11
7
4
8
2
9
1
10
0
∑  = 100</p>
    </sec>
    <sec id="sec-4">
      <title>4. Experimental Results and Discussions</title>
      <p>For determine the characteristics of a period of systematic attacks on the ECS was randomly
selected 100 time intervals of 10 attacks each. The frequencies of successful attacks in these
series are given in Table 1. It is necessary to calculate the theoretical binomial distribution of
probabilities of x successful attacks in one series.</p>
      <p>Here  = 100,  = 10. Using the products of  and   given in the table, we find</p>
      <p>Attacks of 9-10 in the series have almost no efect on the result. Therefore, we can neglect
them. Here instead of determining, and then summing up the probabilities of 0, 1, 2, ..., 8 attacks
(this is nine terms), let’s determine the probability of 9 or 10 attacks (two terms):
 10(9) +  10(10) = 0.1493.</p>
      <p>Then the required value is calculated by the formula (8)</p>
      <p>10( ≤ 8) = 1 − ( 10(9) +  10(10)) = 1 − 0.1493 = 0.8507.</p>
      <p>In other words, if we take 10,000 samples of 10 attacks, then in 8507 samples we can expect
the appearance of no more than 8 attacks and the greatest load on the security system goes
to 2-5 attacks series. By systematizing the statistics of periods of such attacks, it is possible to
predict the following system loads and improve security levels in ECS.</p>
    </sec>
    <sec id="sec-5">
      <title>5. Conslusions</title>
      <p>The authors developed an approach to the analysis of qualitative (absolute frequency of attacks
series on the system per a certain period) and quantitative (relative frequency of attacks series
on the system per a certain period) characteristics to assess the information security risks in
e-commerce systems. It is proposed to use the method of the sequential monitoring to study
information security threats and conduct risk assessments. In this case, the mathematical model
of risk, which provides the results of the test for the hypergeometric law, is the basis for the
construction of other probabilistic models, including those that are widely used in the study of
threats to information security.</p>
      <p>Qualitative and quantitative characteristics of one event from a series of attacks are analyzed.
The analysis clarifies the priority of information security, allowable residual risks and costs of
information security measures. Then it concludes on the allowable residual levels of risk and
the feasibility of using the specific security options. It has been experimentally confirmed on
10,000 samples out of 10 attacks that in 8507 samples, no more than 8 attacks can be expected,
and the greatest load on the security system falls on 2-5 series of attacks.</p>
      <p>In the future, it is expected to investigate the attacks series on information systems depending
on period (day, week, month and season).
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