# Protecting Data at Risk of Unintentional Electromagnetic Emanation: TEMPEST Profiling
## 5 Discussion  
The primary goal of this study was to analyze the scope of existing research on sensitive information and unintentional emission through EM leakage. Various challenges are associated with TEMPEST-protected devices and equipment due to the limited access to TEMPEST standards available only to the US government, NATO, and a selected group of manufacturers and vendors (see Table 9). In the domain of TEMPEST equipment development, there are numerous companies not included in Table 9, such as Advanced Programs Inc (Columbia, MD 21046/USA), Advanced Technologies Institute (Bucharest/Romania), API CRIPTEC (Columbia, MD 21046/USA), ATM Computer Systems GmbH (Konstanz/Germany), EMCON Emanation Control (Kanata, Ontario, K2K 2P5, CA/Canada), Head Italia S.p.A. (Rome/Italy), IDE-INTRACOM Defense Electronics (Koropi/Greece), Siemens AG (Munich/Germany), Secure Systems and Technologies Ltd. (Glouchester/UK), and others. A lot of vendors also sell TEMPEST and zoning equipment worldwide, including cables, connectors, filters, foils, honeycomb vents, shielding glasses, protective tents, TEMPEST gaskets, and waveguides. Although all these companies claim to offer TEMPEST protection (TEMPEST certificates), none of the standards are available to customers. A comparison of devices and TEMPEST protection measurements is shown in Table 10. \begin{table}
\begin{tabular}{c c} \hline \hline
**Author(s)** & **Methodology** \\ \hline [PERSON] et al. (2021) [96] & Use of spatial EM noise generators to prevent from interception of informative signals. \\ \hline [PERSON]; [PERSON] (2018) [97] & Use of EM noise generator as a software technique for obfuscating SCA analysis. \\ \hline [PERSON] et al. (2022) [98] & The cognitive approach to mitigating SCA is not reliant on the architecture or operating system. \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Masking methodologies. \begin{table}
\begin{tabular}{c c} \hline \hline  & **Company** \\ \hline
1 & Digital platforms—S.p.A. (Rome/Italy) \\
2 & Eurotempest BV \\
3 & GBS TEMPEST and Service GmbH (Diepholz/Germany) \\
4 & OSPL Netherland \\
5 & S.C. BLUESPACE TECHNOLOGY S.R.L. (Ilfov/Romania) \\
6 & SILTEC S.p z o.o (Pruszkow, Poland) \\
7 & SIPAL—S.p.A. \\
8 & Thales SIX GTS France SAS (Gennevilliers/France) \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Manufacters of the TEMPEST-protected devices. Complex devices using an AC source for operation create a stronger EM field that results in reading data from a greater distance. TEMPEST equipment manufacturers try to eliminate or reduce the risk of data leakage by implementing TEMPEST-filtered AC input, cable shielding, or EM shields. It is very difficult to reduce this risk to zero, but it can be reduced with appropriate measures. One way is to prevent an attacker from exploiting EM radiation from a safe distance. Another measure of protection is to filter the AC input. Connecting a filter to the device circuit can suppress EM noise transmitted through the line. Power supply filters typically consist of passive components such as inductors and capacitors connected to form an LC circuit. Inductors allow DC or LF currents to pass through while suppressing unwanted HF currents. In this way, the filter removes unwanted current to flow freely. Cables can also be a major source of EMI, both as sources and receivers. The shield works in both directions. First, it can reflect the energy. Second, it can absorb noise and transmit it to the ground. Typically, two types of shielding are used in cables: foil and braid. A foil shield is a thin layer of aluminum, usually attached to a surrounding conductor support. Braids are woven meshes made from bare copper wire or tinned copper wire. Braid provides a low-resistance path to the ground and is much easier to terminate by crimping or soldering when attaching the connector. Protection against unwanted EM emissions also includes placing electronic equipment and devices in Faraday cages or shielded chambers.