Malyuta Maxim

Coming from the generally accepted formulations, a concept «Priv» can be defined as a complex of organizational and technical measures, conducted for prevention of theft, intentional transmission, elimination and unauthorized division to information or loss of information. The problem of defence of secret closely follows with such concepts, as a «loss of information», «source of loss», «channel of loss», «ceiling of channel of loss».

The new factor of threats to informative safety is possibility of the intentional electromagnetic affecting («electromagnetic terrorism») work critically of important objects by electromagnetic influence. Potential vulnerability of the informative systems in relation to casual and premeditated negative influences requires acceptance of adequate protective measures.

Realization of threat of intentional electromagnetic influence is elimination, distortion and blocking of information because of the electromagnetic attacking basic elements of vitally important objects:

• CASS of management basic and ancillary technological proceedings, and also processes of providing of safety of objects;
• elements of the systems of physical defence of objects – checking and access control systems, systems of collection and treatment of information;
• systems of information and connection of objects transfer with the organs of management.

Intentional power electromagnetic influences create a danger for ASZI of the vitally important electronic systems – communication and management networks, bankings systems, systems of power supply et al. The object of electromagnetic influence can be the informative systems of object, systems of physical defence of equipment, supporting infrastructures, ancillaries, systems of power supply, flow lines et cetera the Most detriment at intentional EMV can be inflicted to the objects, at which ASZI are a hardcore with the continuous process of treatment of streams of information.

Intentional power electromagnetic influences can be carried out openly or secretively («camouflaged» under the action of EMIS), by the controlled (on ether) from distance or contact (on a network) method and to be directed on achievement of failure, destruction of the electronic systems et cetera

Radioscreening materials provide the isolation of certain part of space from the source of EMP of this frequency range. For screening of EMP various radioreflecting and radio materials are used in radio frequency ranges. Different metals behave to radioreflecting. They are used as metallic folias, nets, or as grates and metallic pipes.

Application of high–quality screens allows to decide many tasks among which priv in apartments and technical ductings, protecting from intentional electromagnetic influence on ether, tasks of electromagnetic compatibility of equipment and devices at their sharing, tasks of defence of personnel from the enhanceable level of the electromagnetic fields and providing of favourable ecological situation round workings electricmachines and UHF–devices.

Under screening both protecting of devices from influence of the external fields and localization of radiation of some facilities, impedimental to the display of these radiations in an environment is understood in general case. In any case screening efficiency is a degree of weakening of the field (electric or magnetic) constituents, determined as a relation of virtual values of tension of the fields in this point of space in default of and presence of screen.

Theoretical decision of screening task, determination of values of tension of the fields in general case extraordinarily difficultly, therefore depending on the type of the decided task appears comfortable to examine the separate types of screening: electric, magnetostatics and electromagnetic. The last is most general and often applied, because in most cases screening has to be had business either with variables or with fluctuating and rarer – indeed with the static fields.

Theoretical and experimental researches of row of authors rotined that the form of screen insignificantly influenced on his efficiency. A main factor, determining quality of screen, are radiophysics properties of material and construction features. It allows at the calculation of efficiency of screen in the real terms to use his most simple presentation: sphere, cylinder, parralel sheet etc. Such replacement to the real construction does not result in any considerable deviations of the real efficiency from a calculation, because by principal reason limiting achievement of high values of screening efficiency there is a presence in the screen of the technological openings (input–outputs, ventilations), and in the screened apartments – devices of life–support, relating an apartment with an external environment.

At planning of electromagnetic screens it is necessary to mean in general case, that on comparatively LFS it is most difficult to provide the effective screening the magnetic constituent of the field, while screening an electric constituent does not present the special difficulties even at the use of the perforated or reticulated screens.

In spite of that on LFS high–conducting materials can provide the very large values of screening efficiency, in a number of cases (on the technological, structural, economic considering) appears more expedient to apply (especially at screening static and fluctuations of the magnetic fields with the low value of tension) magnetic materials with the high values of initial permeance.

Obviously, that on LFS a steel screen permeance of which can be high (or screen from other electro–conducting material with considerable permeance) enough appears more effective copper on absorption. However for the increase of his efficiency it is necessary to increase the thickness of screening sheet. In addition, with growth of frequency permeance of all materials diminishes quickly, thus the more considerable, than anymore its initial value. Therefore materials with the large value of initial permeance (104 Gn/m) it is expedient to use only to frequencies порядка 1 кГц. At the large values of tension of the magnetic field from the satiation of material of ferromagnetic his permeance falls the sharper, than anymore initial value of permeability.

For avoidance of effect of satiation a screen is done by multi–layered, here desirably, that each a subsequent (in relation to the screened radiation) layer had a greater initial value of permeance, what previous, because the equivalent depth of penetration of the electromagnetic field in the layer of material is back proportional to work of his permeance and conductivity.

Thus, screening of hertzian waves possibly fully to provide electromagnetic safety of object. The concrete value of screening depends on the area of windows, configuration of apartment, his volume and material of walls.

  Without screen            With screen

Actuality of questions of stability of ASZI at intentional EMV is confirmed by the results of vast researches in this area. The accumulated experience of researches and tests of elements of objects of informatization on stability to intentional EMV shows that for providing of steady work of ASZI acceptance of the special organizational–technical measures is needed. Requirements to organization and maintenance of works on protecting of ASZI from intentional EMV, to facilities of defence of ASZI from intentional EMV and to facilities of their discovery regulated by the proper standards in this area.

However providing of requirements on electromagnetic safety of object, especially in the part regarding to a priv from a loss on the technical ductings, created with the use of the special equipment (electro–acoustic channel, radio channel, channel of side electromagnetic radiations and aiming and o. of a.), it is necessary to provide for on the stage of development of project of object. So, for example, at planning within the limits of object it is necessary to select the areas of enhanceable confidentiality are rooms of negotiations, technological apartments, information, intended for the official use, circulates in which, etc. there must not be windows In such apartments, they must have the independent system of power supply, screened doors.