Automatic Tempest Test and Analysis System Design

Boitan²,

Halunga

2020

Applied Sciences

The main topic of the present paper is the printed text protection against electromagnetic infiltration. There are many solutions to protect such data. One of these methods is the one that uses computer fonts that are characterized by special shapes. The suitability of the solution has to be confirmed by many tests and analyses. An important element of such researches is the class of receiving devices used. In the case of measurements of the valuable emissions arising from electronic data processing of the printed text, typical receivers that are used for measurements of electromagnetic compatibility cannot be used. They have to be dedicated devices for measuring the very low level of signal that arises unintentionally. The sensitivity of the receiver must be very high in wide measuring bands. In addition, in order to assess the method of preventing electromagnetic infiltration, it is important to verify it by independent institutions. An additional advantage is the use of different receivers in the assessment process. This paper presents the results of studies made regarding the suitability of two sets of fonts with special shapes (secure symmetrical and secure asymmetrical) in secure information processing. The analysis of the fonts was based on visual examination, a basic method of preliminary assessment of electromagnetic emissions correlated with processed text information, of the images reproduced from unwanted emissions. The tests were carried out at two independent institutions, Military Communication Institute—Poland, Special Telecommunications Services—Romania, using three different types of receivers: Tempest Test System DSI-1550A, Rohde & Schwarz FSET22 and Rohde & Schwarz FSWT. The images obtained in the two independent laboratories with different setup and test equipment confirmed thus without doubt the possibility of using special fonts as the solution against an effectiveness of electromagnetic infiltration. The above assessment is correct, regardless of the used receiver and the environment of implementation of the secure fonts.

Section: Military Communication Institutementioning

confidence: 99%

Assessing the Security of TEMPEST Fonts against Electromagnetic Eavesdropping by Using Different Specialized Receivers

Boitan²,

Halunga

2020

Applied Sciences

“…11 includes fragments of the reconstructed images. Certainly the quality of the pictures is not good [25][26][27][28]. It is caused by very weak signals and disturbances inside SCA [29].…”

Section: Character Error Rate (Cer)mentioning

confidence: 99%

TEMPEST Font Protects Text Data against RF Electromagnetic Attack

2020

Teh. vjesn.

Nowadays an electromagnetic penetration process of electronic devices has a big significance. Processed information in electronic form could be protected in different ways. Very often used methods limit the levels of valuable emissions. But such methods could not always be implemented in commercial devices. A new solution (soft tempest) is proposed. The solution is based on TEMPEST font. The font does not possess distinctive features. This phenomenon causes that at an output of Side Channel Attack the possibilities of recognition of each character which appears on the reconstructed image for sources in the form of graphic lines (VGA and DVI) are limited. In this way the TEMPEST font protects processed data against electromagnetic penetration not only for VGA and DVI standards. The data are protected during printing them on laser printers too.

“…The radiated emission propagates in the space around the source and is subject to SCA (i.e., a filter acting the same way as a high-pass filter). As a result of such original signal distortions, the high-pass filtration of the (TMDS) coded signal, and the effect of the reception band of the measuring receiver (signal module), the form of compromising emanations becomes fully usable in the process of electromagnetic infiltration [29]. Figure 7 presents the image obtained from the signal shown in Figure 6b subjected to the abovementioned operations (calculating the derivative, i.e., the operation equal to the effect of a high-pass filter and calculating a signal module).…”

Section: Transition Minimized Differential Signaling (Tmds) Codingmentioning

confidence: 99%

The Effectiveness of TMDS Coding in Counteracting the Non-Invasive Acquisition of Graphic Data

Przybysz

2019

Electronics

Modern video display terminals commonly use digital video signals. Transition minimized differential signaling (TMDS) coding implemented in video signal transmission using DVI (Digital Visual Interface) standard is commonly used. The aim of the coding scheme adopted by this solution is to eliminate the constant component of the electrical signal, increase the resistance to electromagnetic (EM) interference, and reduce electronic interference between cables. Professionals and hobbyists interested in the problems relating to protecting information against electromagnetic infiltration believe that TMDS coding, in contrast to the VGA (Video Graphics Array) analogue standard, significantly improves the electromagnetic security of processed graphic information. This paper shows a comparison of the abovementioned standards in terms of information protection against electromagnetic infiltration. The paper presents the results of computer simulations and studies dealing with practical compromising emanations for DVI standard and its susceptibility to electromagnetic radiation spying. The obtained results show that the commonly expressed ideas of digital standards being fully secure are false. The obtained test results show that the level of electromagnetic protection can be increased by using appropriate pairs of colors for the text and background. This solution has to be connected with a mode that smooths the edges of graphic signs. Then, the number of frequencies in which valuable emissions exist can be limited. In this paper, pairs of colors for which the level of protection of information can be increased are shown. The authors present their analyses on the basis of the method of colors. The method is connected to possibilities of selection of smoothing modes of edges. As Windows is the most commonly used system in classified work stations (so-called TEMPEST computers), this operating system was considered from the viewpoint of the protection of processed information.