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problems ofcontrol. Vilnius. IM Lit.A.Sci., 1978. N 28. 139 p. [In Russian] 12. Lipejko A.M. Classification ofautoregression sequences with jump-like varying parameters //Statistical problems of control. Vilnius: IM Lit.A.Sci., 1978. N 30. P.9-27. [In Russian] 13. Kravchenko N.I., Bezruk V.M., Tikhonov V.A. Recognition of random signals in the framework of autoregression model // Probabilistic models and random signals and fields procession. K: YMK BO, 1991. P. 138-142. [In Russian]. 14. Kravchenko N.I., Bezruk V.M., Tikhonov V.A. Structures of devices for recognition of Gauss signals with their description by the autoregression model / /Radio Electronics and Informatics. 2001. N 4. P.49-54. [In Russian] 15. Bezruk V.M., Tikhonov V.A., Tikhonov V. V. Recognition by the grid filter reflection coefficients // ACS and automation devices. 2001. N° P.36-39. [In Russian] 16. Senin A.G. Random signals recognition. - Novosibirsc: Nauka, 1974. 76p.[In Russian] 17. Libenson M.N. Non-linear statistical method of many classes recognition //Problems od random search. Riga: 1978. N 6. P. 299317. [In Russian] 18. Omelchenko V.A. Signals’ recognition by the power spectrum in the optimal Karunev -Loev basis // Izv. vuzov. Radioelectronics. 1980. N°12. P.11-17. [InRussian] 19. Omelchenko V.A. Foundations of spectral theory of signal recognition. Kharkov: Vyshcha shkola, 1983. 156p. [In Russian]. 20. Omelchenko V.A., Balabanov V.V., Bezruk V.M., Omelchenko A.V., Fefelov N.A.
Recognition of non-completely described random signals in the presence of unknown signals class //Information choice and procession. Kiev: A.Sci. of Ukraine, 1992. N 8. P.71-80. [In Russian]. 21. Bezruk V.M., Kovalenko N.P. Synthesis and analysis of Gauss random signals algorithms in the presence of unknown signals class on the basis autoregression model //ACS and automation devices. 2000. N111. P.115-120. [In Russian]. 22. Omelchenko V.A., Bezruk V.M., Kovalenko N.P. Recognition of preset radio signals based on autoregression model //Radiotekhnika: All-Ukr. Sci. Interdep Mag. 2001.N123. P.195-199. [In Russian]. 23. Bezruk V.M. Optimization ofautoregression algorithms signals recognition by the totality of quality indices //Information-control systems in railway transport. 2001. N° 2. P. 10-13. [In Russian]. 24. Tikhonov V.A. Generalized model of non-Gauss processes autoregrression / / Radiotekhnika: All-Ukr. Sci. Interdep.Mag.- 2003. N° 132. P.7882. [In Russian]
Bezruk Valery Mikhailovich, Candidate of Techn. Sci. Ass. Prof., Net Communications Department, Kharkov National University ofRadio Electronics. Scientific interests: simulation and multicriterial optimization of signals’ recognition systems. Address: Lenin Ave., 14, KNURE, Kharkov, 61166, Ukraine. Telephone for contacts: 7021426. E-mail: bezruk@kture.kharkov.ua.
OBJECTIVE-ORIENTED META-LANGUAGE OF SIMULATION IN DESIGNING
KUZEMIN A.Ya.
Professor, Cand. Techn. Sci.
Kharkov National University of Radio Electronics, Faculty of Applied Mathematics and Management, Information Science Department, Danilevsky Str.,15, App.8, Kharkov,61058, Ukraine kuzy@.foss.kharkov.ua,_kuzy@kture.kharkov.ua
Problems of designing operate with the system-complex objects. When considering these problems it is necessary first of all to introduce some terminological stipulations. An object is something opposing to a subject or is the aim of its activity in its subject-practical activity in the frameworks of designing. At the stage of identification to reach the aims of designing a subject (or “designer”) should as if “pass ” into the state of an object (“to foresee behavior of the system being designed”). In this case the object simulates the response activity of the source i.e. subject. In other words, the subject must become the object for rightness perception of the context understanding of its knowledge, abilities, experience in object-oriented presentation of the solution versions in designing. Without such an organization of the subject and object communication we can’t reach not only the preset global aims but structurally dependent sub-aims on designing as well. T o plan each next stage in designing one should be, as a minimum, sure that the object understands right the previous stage context. Such an intelligence of the interaction process of the subject-object couple results in self-organization. The chosen intelligence can result in constructing intelligent systems for designing.
The object as the aim of designing represents the system of the connected objects (subsystems) of a lower level. Investigations into the psychology field showed that the human brain percepts information in portions and due to the
hyper geometrical growth of the latter copes with it only aligning the objects in the logically linked hierarchy. Thus, the surrounding world is a hierarchic one for a modern man and a man in a general case conceives with patterns-objects and data and knowledge (properties, actions, concepts etc.) connected with them.
The main element of the used methodology for solving the preset problems is the object-oriented analysis [1,2], where the requirements to the designing system are perceived in terms of classes and objects chosen in the subject field. The analysis process is tightly connected with classification process:
classical categorization (the classified objects are subdivided into non-crossing sets by some feature inherent only to the given set);
conceptual clusterization (judgements are based on the best “agreement” between the criteria by the function of belonging to the odd set);
prototype theory (the object is classified by the “degree of similarity” with some standard).
The process of development of the designing system joins in itself the process of the objective decomposition and presentation methods of the logical, physical, static and dynamic models of the systembeing designed. It is a common practice to link such an approach with the concepts of the obj ect-oriented designing (OOD) [1,2]. Further we will proceed from the fact that classes and objects were separated in the course of the process of the system and object-oriented analysis. But accepting the problem of the optimal identification of all object-oriented concepts of the subject field (complete formalization) unsolvable to the full extent it is possible to introduce the identification quality criteria (for example, linkage, connectivity, sufficiency, completeness) of both the system being designed as a whole, and its parts [1,2,3]. In this case some standard for the set of objects with a general structure and common behavior should be understood as a class. We will consider that the object is characterized by the state, behavior and identity. The
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possibility of the formal representation of the system being designed canbe illustrated with the generalized example. Let us consider interaction of some classes in pairs. Then the relation between them can be classified in terms of the theory of binary relations on sets. Aggregation relation (usage) will be transient and antisymmetric one. Really, let the class A includes the class B, and the class C contains in itself the class A, then C contains in itself B (but B is accessible in C only through the methods from A if it is envisaged by the sufficiency), really the class contains itself. If every class in the heritage hierarchy is considered to be the chain link then the axiom as the heritage chain can’t be closed. In this case the aggregation (use) relation is transitive and asymmetric and the heritage relation is transitive and anti-reflexive. The validity of the aforesaid can be demonstrated starting from the assumption about the binary nature of relations between the classes. Really, let A inherits from B (“If A is not B it shouldn’t inherit from B”), then if C inherits from A, in such an event C inherits from B as well. Transitivity is proved. Let us show that antireflexiveness due to our axiom there is not a single class which would be the super class to itself. In this case it must be emphasized that the concept of the class is inseparable from the subj ect field fo r which it was singled out. This imposes the main limitations on the formalization degree. Therefore one never should consider a class as a set without its semantic meaning in the subject field. The latter can be considered a designing axiom. This is an actual recognition of the necessity to use the context dependent languages of simulation when designing. But every class having predetermined structure and obeying definite rules of designing reflects the concept of the subjective field. Newly generated classes must also reflect the concept of the subjective field (have heritage). It is very important both in the classes separation and formal description ofthe designing process not to loose the object of designing i.e. not to simplify it to an extent that the subject properties to be designed in future will be lost. Here the designing of the system by steps as if repeating the system emerging story is the single way out
[4].
Two types of classes are singled out in the OOD: the classes representing applied concepts and classes-artefacts of realization [2]. The second ones add the first ones. The first ones bear the greater part of the linkage, connectivity quality, the second ones assist realization of ideas of the first and bear the load of sufficiency, completeness and primitiveness. The object of the class-realization obeys all the pre-conditions of its encapsulated functions which were used (induced) in the process of work and corresponds to all their post-conditions. It should be noted that the formal axiomatic theory requires the formal language of mathematical logic.
So it is possible to perform the following mathematical description of the OOD system of designing in the general form. From the primary symbols such asa,b,...,0,1,...n the final set of their one-place assemblies is formed, then their subsets will be referred as the first order set. Descartes set product is formed of the first order sets, it is said to be the Descartes first order product.
Definition 1. Descartes set product subset will be referred as
the relation.
For example,
(a,b, c,), (a, d, k), (m, d, k) c {a, m} x {b, d, l} x {c, k}.
Using relations of the first order it is possible to form the system of their one-place assemblies, the subsets of this system are the sets of the second order. Using the sets of the second order it is possible to form Descartes products of the second order, the second order relations being their subsets:
{(0,0,1), (1,0,1), (1,1,1)}, {(0,1,1), (1,1,0^ - the first order relations; {{(0,0,1),(1,0,1),(1,1,1)},{(0,1,1),(1,1,0^} - the second order sets;
{(a,{(0,0,1),(1,0,1),(1,1,1)}),(b,{(0,1,1),(1,1,0)})} - the second order relations.
Operations of unification, intersection, addition, difference, symmetrical difference can be performed with the relations. Relations can be of different degrees. The first degree relations unite objects, the second degree relations unite the first degree relations. The transitivity relation can serve as an example of the second degree relations.
Definition 2. Any function P(xj, x2 , xn) = £ reflecting
the set Un into the set E = {0,1 is said to be the n -place predicate set on Un . The argument xi (i = 1,n) of the
predicate P(xj, x2 , xn) is said to be dummy or unessential
if Vx1,...,xi_1,xi,xi',...,xn e U an equality
P(x1 v- xi=1,x/ , x!+1 ,...xn ) = P(x1 v- x!=1 , xn , x!+1 ,...xn )
takes place. The predicate where all the arguments except one are unessential is referred to as the unary predicate, except
two - the binary predicate, m(m < n), m -ary.
The predicate of the object “recognition ” is said to be the predicate: a e U, xi, i = 1, n, x* e M , M is the set of all
predicates if x
1, xi = a; 0, xi ^ a.
Definition 3. Any system offormalnotation of A set elements is referred to the algebra A over the set A. The set A is said to be the support of the algebra A Any Algebra is characterized by a set of the basic operations reflecting the set A into itself and into the set of A basic elements. The set of all the basic operation of the algebra A is said to be the basis of the algebra A operations. The set of all the basic elements of algebra A is said to be its elements ’ basis. The operations basis and elements basis form the basis of algebra A. The formula of the algebra is said to be the notation expressing some superposition of the algebra basic operations used by it to its basic elements. The algebra over A is said to be complete if its formula can express any element of the set A.
The predicates algebra overM - set of all predicates is said to be any algebra whose support is the set M - all the predicates on Un. The model over the spaceUn is said to be any pair (M, P), where some nonempty subset N ofthe space U n acts as the first component and in the role of the second component is some predicate P, defined on Un. The relation M is said to be the support of the model (M, P) and the predicate is said to be the model predicate.
Let U be the universe of the subjects of theory T. (xj, x2,....,xn) are the subject variables. M is the set of all predicates P(x1,x2,....,xn) on the space UnM is the universe of predicates. Predicates X1,X2,...,Xn defined on
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the set m are said to be the predicate variables; the predicates preset on Un serve as the predicates’ values. The set Mn is said to be the predicate space ofn dimensionality. Elements
of the set Mn are said to be the predicate vectors. Any
functionf(xj,X2,...,Xn) = Y reflecting the setMn intoM is said to be the predicate operation. The operations of conjunction, disjunction and negation are defined over the predicate operations:
F(X1,...Xn) = F(X1,...,Xn),
(F a Q)(X1,...,Xn) = F(X1,...,Xn) a Q(X1,...Xn)
The predicate operation of recognition of the predicate P by the variable Xi, i = 1, n is said to be the operation:
F(X1,...,Xi,..,Xn)
1,Xi = P; 0,Xi * P.
(a, b, pf, pl) c {a} x {b} x {pf} x {pi}
It is known that the predicate can be defined using every relation: P(x13x2,x3,x4) = x1ax2xpfxpi;
x1 = a
P(x 1, x 2 , x 3 , x 4 ) = 1
x2
x3
b
pf
lx4 = pi
Let us suppose that we want to add one more field into our structure, namely, a variable of the bool type. The given operation will result, on one hand, in the Descartes multiplication and, on the other hand, in the predicate P disjunction with a new predicate Q, preset on the multiplied
set: {f_t}, Q = x5_t, P a Q = x1ax2xpfx41 • xp,
predicate P A Q is true on (a, b, pf, pl, f_t) .
The operation of change of the argument predicate xt for Xj is said to be the operation xijxj (P) = Q, which brings every predicateP(x 1,x2,...,xn) in correspondence with the predicate Q(x1,....xm ) according to the following rule Va1,...,ai,...,aj,...,am e U ; the followingequality takes place
Q(aiv,aiv:> ajv:> am) = P(aiv:> aiv:> ajv:> am).
The substitution xt/a(P) = Q of the value a for the argument Xi is said to be the operation, which brings every predicate P(x1,..,xi,...,xm) in correspondence the predicate Q according to the following rule:
^a1v,aiv,ajv,am G U Q(al,■■, ar v. am ) = P(al,■■, a,■■, am ).
Operations of change and substitution can be understood not only as the predicate operations but as the operations on the predicate operations. In this context the operations are written as, for example:
xi/a(F(X1v,Xn)) = F(x1/a(X1),...,x1/a(Xn)).
It is possible to present separation of classes and relations between them using formalization ofthe basic concepts ofthe object-oriented designing and programming i.e.
encapsulation, inheriting and polymorphism.
Encapsulation. The concept of the class unites the concept of the structure - type of a user which is on the one hand nothing but the class where all the data are open and on the other hand it is the Descartes sets’ product. Thus, the structure can formally be described as the relation:
stuct
{
int a; float b; float (* pf)(); int (*pi)();
}
Assume next that our aim is to get a structure of two others in such a way that the first element of one (the first) of them was changed for the first element of the other (the second) one:
struct struct
{ { int a; int b; float c;
} A1;
int m; int l;
} A2;
PA1(x1,x2,x3) = xi3x2x3
PA2(y1,y2) = ymy2
Pa, a Pa2 = x[x2x3 • ymy2(*)
(*) gives us the relation (a, b, c, m,l), and not (b, c, m, l), so it is necessary to perform one more operation i.e. the operation of substitution:
xi/a(PA, a PA2)
a b c m l
a x2x3y, y2
1,
thus the predicate Q - x,/a(PA, A PA) gives us the relation (b,c, m,l). Encapsulation assumes both simultaneous “storage” of data and functions processing these data and access restriction. The class is a structure, which has public, protected, private parts of interface. It seems logical to present the class as a relation of relations:
((al,a2,••••,an),(b1,b2,
,bm),(C1,C2,••••,Ck)),
where n < m < k for definiteness and the first relation corresponds to the open part of the class, the second relation corresponds to the protected part of the class, the third relation corresponds to the closed part of the class.
Inheriting. With inheriting the descendent has the access only to the protected and open interface parts of is parent. In other words the descendent substitutes the closed part with its closed part and adds the open and the protected ones. As now taking into account the encapsulation we have to deal with the relation of relations then every relation should be compared with it predicate: by this means the transition from
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the predicate algebra to the predicate operations ’ algebra will take place.
An x Bm x Ck
U
M=m+m+k
((ai,a2,....,an),(b1,b2,...,bm)>(c1>c2v->ck))
X1 = P1(x1,...,xn) = x^2 •...• xnn
X2 = P2(Y1,-,Ym) = Y11Y22 • ••• • y
X3 = = Z1C1 z22 ■ ... •z
m
m
Q = P(X1,X2,X3) = X1X2X3.
In the given case the operation of substitution exists:
xi /a (Q) = x^a (X1) • xja(X2) • x^a (X3) .
Thus, the inheriting can be formally presented by a sequence of operations:
1. Predicate operations disjunction.
2. Substitutions execution.
user’s name is added with a number of the bytes being returned and the type and quantity of the received parameters are coded, thus the functions being overrun by the compiler transformed into different functions, for example:
int f();//error
int* f ();//error
will be transformed in one name __f@4, this, naturally, will cause an error! Therefore the polymorphism reached with such syntactic structures shouldn’t be used. The functions are considered to be different.
Polymorphism through virtual functions. If a function is declared avirtual one in C++language it canbe overdetermined (with the same quantity of parameters and the same returned value) in the descendant class. The following means (one at a time or simultaneously) are formally offered to use for writing the polymorphism:
- either to introduce nonexistent variables with their further definition;
((al,a2,••••,an),(b1,b2,...,bm),(c1,c2, .,ck)):P1
((an+1, an +2 ,..., an+j1 ), (bm+1, bm+2, bm+j2 )> (ck+1,ck+2,...5ck+j3 )) : P2
P1 = X1X2X3, P2 = Y1Y2Y3
P1 A P2 = X1X2X3Y1Y2Y3 =
a1 a2 bi x11 •... • xn2 • Y11 • bm - • Ymm • c. Ok z11 •... • zkk . V an +1 . . xn+1 •••
x"^ • ym^ •...• y bm+j2 _ m+j ••• ry ck +1 ry * Zk+1 * ... * ^ ck+j3 k+j3
zi/ci(P1 A P2 ) = Q =
a1 a2 b1 x11 •... • xn • y11 •. • ybm . m cc1 • • cck c1 ... ck xn+1 ...
xan+j1 _ ybm+1 . . xn+j1 Ym+1 ... ybm+j2 , •Vm+j2 zck+1 ... zk+1 .' . z°k+j3 _ '. k+j3
a1 a2 b1 = xi •... • xn • Y11 • • yV m . x an+1 . . xn+1 ... xan+j1 . ybm+1 xn+j1 Ym+1
ybm+j2 ^m+j2 . . zck+1 . . zck+j3 ... k +1 ... k+j3
On calculating, the predicate operation Q is true if and only if its predicate variables are preset in the relation
((a
1,a2 ,.,an+j ),(b 1, b2 ,•••, b m+j2 ),(ck+1 , ck+2vck+j3 )
Polymorphism is reached by means of the programming language and consists in representation of one interface with all the methods ofthe class. Polymorphism is ensured through the overrun functions. It should be noted that for T1 f(T2i); T3 f(T4i); or with the means of the pro gramming language:
int f();//right int f (int);//right int f (float);//right void f ();//error float f ();//error
But it should be taken into consideration that the compiler C++ presents the functions deteriorating the names; here the
- or to introduce the substitution operations
xi/xj(P1 A P2 ) = x7xj(P1) A x7xj(P2), where xj coincides with xi on the relation pn and differs on the relation pn+k.
The inherit relation competes with the aggregation relation. In this case the aggregation relation formally looks like
((a1,a2, .,ar, .,an),(b1,b2, .,bm),(c1,c2, .,ck)) ,
where ar = (ar,,..., ar, ) is the relation. The predicate variable X1 (predicate) will contain the predicate as a variable X1 = x1 • XP, rge p is the predicate preset on (ari ,..,arj) , ie. p = ar.
Thus, to represent formally relations between the classes the predicate operations algebra with the variable basis containing the object recognition predicates, the predicate recognition pie dicates and operations ’ basis consisting of the disjunction, substitution and change operations is needed.
A question was raised as to the completeness ofthe introduced algebra of predicate operation. It should be noted that the introduced algebra differs from the applied algebra in the absence of negation operations and presence of the substitution operation and the predicate recognition predicates.
The natural generalization of the classes representation is the model preset on the medium i.e. the Descartes set product:
An = AN1 X...X AN", N = N1 +... + Nn
Bm = BM1 X... X BMm, M = M1 +... + Mm
CK = Cf1 X... X CKk,
K = K1 +... + Kk,N < M < K for the definiteness;
UL = AN x Bm x CK,L = N + M + K- setUL and predicate operation Q, set on UL, (UL, Q).
In the object-oriented designing the associations as the relations between classes are being made clear when passing from inheriting to aggregation with the estimate by the criterion: can the class have several of “this”. First the
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inheriting algebra is built and then the aggregation algebra. The first algebra is sub-algebra of the second one.
Conclusion
The OOD system of designing partitions the problem of its development into sub-problems. Using the object-oriented decompo sition in designing it is possible to build the systems taking them into consideration both the hierarchy of their structure and the hierarchy withtheir “emerging”. The process of designing with a sufficient range of accuracy can be formalized. Formalization will make it possible to limit the complexity of the system understanding and the designing process itself. The process of designing the classes (the description itself) is formalized with different depth. The classes-realizations being the basis of the system can (or must) be formalized completely; they do not bear in themselves the abstractions of the subject field and they are often the reflection of well-studied concepts in programming (lists,
arrays, classes realizing the access to the storage, files). Classes bearing the load of the subj ect field abstractions are designed with allowance for understanding of their structure or emergence. In this case formalizationis directed on revealing of the depth of investigation, the interface completeness but not on the complete description of the structure on the basis of which it is possible to advocate the correctness of the classes arrangement.
References: 1. Buch G. The Object-oriented analysis and designing with examples of appendices on C ++, Publishing house/translation from English. Moscow: Publishing house Bin, NEVA PROSPECTUS, 1998. 560 p. (in Russian). 2. Straustrup B. The programming language C ++ // In two parts. Translation from English. Kiev:DIA Software, 1998. 564 p. (in Russian). 3. Kuzemin A.Ya. Object-oriented technology of the information system programming means design. Artificial intelligence // Specialized issue. Proc. ofVII International Conference KDS-99. Kiev-Donetsk. 1999. P.219-226. ( Russian)
VULNERABILITIES i TEST OF INTERNET PROTOCOLS
Volodymyr NEMCHENKO1, Andru SCHAFF
1 - Kharkov National University of Radio Electronics (vpn@narod.ru); 2 - LORIA, ESIAL, UHP Nancy 1, France (Andre .Schaff@loria.fr)
Abstract. This paper argues the necessity ofprotection ofinformation in the distributed systems. Then the analysis of attacks and its classifications are presented. The sequence of operations of the test generation for the network protocols is shown and is concluded by an example.
Every Local Area Network (LAN) connected to the network risks to be attacked via Internet [1]. The quantity of attacks via Internet grows with an increase of the Internet host number as it is exhibited in a fig. 1. [Information of CERT -Computer Emergency Response Team - http://www.cert.org].
Attacks Hosts
1988 1989 1990 1991 1992 1993 1994 1995 - Years
of the Internet protocols. There are different classifications, but almost of them are not completes. The fig. 2 presents the more complete classification composed of six independent classifications [2].
Classification 1: The attacks can either change or not change the operation of a system. It conforms to the active or the passive attacks. Let’s mark, that the majority of attacks is active.
Classification 2: The purpose of attack can be different but it is usually the corruption either of the confidentiality or of the information integrity or of the deny to services.
Classification 3: Attack cans begin if some condition have place in system. For example, attack starts if the host sends some inquiry or some definite event has place into the system. An attack can be start also without any condition.
Classification 4: If the server, which attacks, waits the answer from his victim it means, we have the attack with feedback. Otherwise, there is attack without feedback.
1. Influence
1.1. Passive 1.2. Active
2. The purpose of attack
2.1. Confidentiality of information 2.3. Deny of service
2.2. Integrity of information
3. Attack beginning condition
3.1. After inquiry 3.3. Without conditions
3.2. After definite event
4. Feedback
4.1. With feedback 4.2. Without feedback
5. Disposition
5.1. Intra segmental 5.2. Inter segmental 6. OSI model
6.1. Physique 6.5. Session
6.2. Channel 6.6. Presentation
6.3. Network 6.7. Application
6.4. Transport________________________________________
Fig. 2. Classifications of attacks in distributed systems.
Fig. 1. Increase of attacks number in Internet: - Internet
host number; - Number of attacks in Internet
The frequently feeble computer protection in LAN aggravates a situation. Even more, the maj ority of the system managers do not find out the fact ofattack on their LAN. Among other factors, the vulnerability of the network protocols plays a big negative role too. All this justifies the analysis necessity of a situation at this area and this is the principal objective of this paper.
The attack against a system has the purpose to reveal its vulnerabilities and to execute attack. It is necessary to classify all possible attacks via Internet for analyze the vulnerabilities R&I, 2003, Ns 3
Classification 5: The server, which attacks, and his victim can be placed in the same segment or in the different segments. By the way, in practice the majority of attacks is intrasegmental.
Classification 6: The attacks can be classed depending on a level of model Open System Interconnection (OSI) where they happen.
Naturally, every attack can be classed by different ways using the different classifications simultaneously. For example, an attack, when some server use “sniffed’ to receive
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