{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,15]],"date-time":"2025-10-15T10:28:33Z","timestamp":1760524113940,"version":"build-2065373602"},"reference-count":31,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2020,11,20]],"date-time":"2020-11-20T00:00:00Z","timestamp":1605830400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>The protection of information processed electronically involves a large number of IT devices from computer sets or laptops to monitors, printers, servers, etc. In many cases, classified information processing might be associated with the use of projectors, which are an indispensable element of meetings for a limited group of people. Such devices are connected to computers through interfaces of various analogue and digital standards and can become an additional source of unwanted emissions, and the distinctive features of these emissions allow the information displayed to be unwantedly reproduced. This paper offers evidence of the existing threat related to electromagnetic infiltration of several projectors, by showing images reconstructed from registered revealing emissions. The paper presents an analysis of several solutions that can be used to reduce the level of infiltration susceptibility of projectors or to highlight this property in the device assessment process. The possibilities of using special computer fonts and the so-called method of colors\u2014background color and text color\u2014is analyzed. The tests were carried out on randomly selected projectors in two independent laboratories, and, based on these results, a number of interesting conclusions have been highlighted at the end.<\/jats:p>","DOI":"10.3390\/sym12111908","type":"journal-article","created":{"date-parts":[[2020,11,20]],"date-time":"2020-11-20T09:46:18Z","timestamp":1605865578000},"page":"1908","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Method of Colors and Secure Fonts Used for Source Shaping of Valuable Emissions from Projector in Electromagnetic Eavesdropping Process"],"prefix":"10.3390","volume":"12","author":[{"given":"Alexandru","family":"Boitan","sequence":"first","affiliation":[{"name":"Special Telecommunications Services, Splaiul Independentei St., 060044 Bucharest, Romania"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5404-3987","authenticated-orcid":false,"given":"Ireneusz","family":"Kubiak","sequence":"additional","affiliation":[{"name":"Department of Electromagnetic Compatibility, Military Communication Institute\u2014National Research Institute, 05-130 Zegrze, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7028-3921","authenticated-orcid":false,"given":"Simona","family":"Halunga","sequence":"additional","affiliation":[{"name":"Telecommunications Department, University Politehnica of Bucharest, 060042 Bucharest, Romania"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Artur","family":"Przybysz","sequence":"additional","affiliation":[{"name":"Department of Electromagnetic Compatibility, Military Communication Institute\u2014National Research Institute, 05-130 Zegrze, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andrzej","family":"Sta\u0144czak","sequence":"additional","affiliation":[{"name":"Department of Electromagnetic Compatibility, Military Communication Institute\u2014National Research Institute, 05-130 Zegrze, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,11,20]]},"reference":[{"key":"ref_1","unstructured":"(2020, October 13). TEMPEST and EMS Policy, Available online: https:\/\/www.ncsc.gov.uk\/information\/tempest-and-ems-policy."},{"key":"ref_2","unstructured":"(2019). Information Assurance Security Guidelines on Accreditation of EU TEMPEST Companies, Council of the European Union, The General Secretariat. Available online: https:\/\/data.consilium.europa.eu\/doc\/document\/ST-7887-2019-INIT\/en\/pdf."},{"key":"ref_3","unstructured":"(2009). NATO Standard (2009) SDIP-27\/2: NATO TEMPEST Requirements and Evaluation Procedures, NATO Military Committee Communication and Information Systems Security and Evaluation Agency (SECAN), Supreme Headquarters Allied Powers Europe (SHAPE). (Published March 2016 but not for Publicuse, NATOCONFIDENTIAL)."},{"key":"ref_4","unstructured":"(2013). EU Standard (2013) IASG 7\u201303: Information Assurance Security Guidelines on EU TEMPEST Requirements and Evaluation Procedures, General Secretariat of the Council of the European Union (GSC). (Published March 2016 but not for Publicuse, EUCONFIDENTIAL)."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Macovei, A., Butnariu, V., Boitan, A., Rosu, G., Trip, B., and Halunga, S. (2018, January 4\u20136). Detection of Electromagnetic Emissions Transmitted on the Power Line Through Electrical Conduction. Proceedings of the International Conference on Applied and Theoretical Electricity (ICATE), Craiova, Romania.","DOI":"10.1109\/ICATE.2018.8551437"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Kubiak, I. (2019). Font Design\u2014Shape Processing of Text Information Structures in the Process of Non-Invasive Data Acquisition. Computers, 8.","DOI":"10.3390\/computers8040070"},{"key":"ref_7","first-page":"1","article-title":"Automatic Tempest test and analysis system design","volume":"4","author":"Ulas","year":"2014","journal-title":"Int. J. Cryptogr. Inf. Secur."},{"key":"ref_8","unstructured":"Kuhn, M.G. (2004). Compromising Emanations: Eavesdropping Risks of Computer Displays, University of Cambridge. Technical Report No.577; UCAM-CL-TR-577."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1826","DOI":"10.1109\/TEMC.2017.2699479","article-title":"Investigation of unintentional video emanations froma VGA connector in the desktop computers","volume":"59","author":"Zhang","year":"2017","journal-title":"IEEE Trans. Electromagn. Compat."},{"key":"ref_10","first-page":"207","article-title":"Video signal level (colour intensity) and effectiveness of electromagnetic infiltration","volume":"64","author":"Kubiak","year":"2016","journal-title":"Bull. Pol. Acad. Sci. Tech. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1129","DOI":"10.1109\/TEMC.2018.2881304","article-title":"Influence of the method of colors on levels of electromagnetic emissions from video standards","volume":"61","author":"Kubiak","year":"2018","journal-title":"IEEE Trans. Electromagn. Compat."},{"key":"ref_12","first-page":"1097726","article-title":"Video signal recovery from the laser printer LCD display","volume":"Volume 10977","author":"Boitan","year":"2018","journal-title":"Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies, IX"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Kubiak, I., and Loughry, J. (2019). LED Arrays of Laser Printers as Valuable Sources of Electromagnetic Waves for Acquisition of Graphic Data. Electronics, 8.","DOI":"10.3390\/electronics8101078"},{"key":"ref_14","unstructured":"Grzesiak, K., and Przybysz, A. (2010). Emission security of laser printers. Concepts and Implementations for Innovative Military Communications and Information Technologies, Military University of Technology. Available online: https:\/\/www.wil.waw.pl\/artprac\/Emission_security_of_laser_printers.pdf."},{"key":"ref_15","first-page":"1354","article-title":"Laser printer as a source of sensitive emissions","volume":"26","author":"Kubiak","year":"2018","journal-title":"Turk. J. Electr. Eng. Comput. Sci."},{"key":"ref_16","unstructured":"Vuagnoux, M., and Pasini, S. (2009, January 10\u201314). Compromising Electromagnetic Emanations of Wired and Wireless Keyboards. Proceedings of the USENIX Security Symposium, Montreal, QC, Canada. Available online: https:\/\/static.usenix.org\/events\/sec09\/tech\/full_papers\/sec09_attacks.pdf."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Boitan, A., B\u0103rtu\u0219ic\u0103, R., Halunga, S., Popescu, M., and Ionu\u021b\u0103, I. (2017). Compromising Electromagnetic Emanations of Wired USB Keyboards. International Conference on Future Access Enablers of Ubiquitous and Intelligent Infrastructures, Springer.","DOI":"10.1007\/978-3-319-92213-3_6"},{"key":"ref_18","first-page":"15","article-title":"Study of Compromising Emissions of PS\/2 Keyboards by Correlative Methods","volume":"65","author":"Rognean","year":"2020","journal-title":"Rev. Roum. Des Sci. Tech. Ser. Electrotech. Energetique"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Trip, B., Butnariu, V., Velicu, V., Halunga, S., and Boitan, A. Analysis of PS\/2 Compromising Emanations. International Conference Advanced Topics in Optoelectronics, Microelectronics and Nanotechnologies (ATOM202020\u201423 August 2020, Constanta, Romania), [10th ed.]. in press.","DOI":"10.1117\/12.2571338"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1016\/0167-4048(90)90157-O","article-title":"The threat of information theft by reception of electromagnetic radiation from RS-232 cables","volume":"9","author":"Smulders","year":"1990","journal-title":"Comput. Secur."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Boitan, A., Halunga, S., B\u00eendar, V., and Fratu, O. (2020). Compromising Electromagnetic Emanations of USB Mass Storage Devices. Wirel. Pers. Commun., 1\u201326.","DOI":"10.1007\/s11277-020-07329-8"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Wampler, C., Uluagac, S., and Beyah, R. (2015, January 6\u201310). Information leakage in encrypted IP video traffic. Proceedings of the 2015 IEEE Global Communications Conference (GLOBECOM), San Diego, CA, USA.","DOI":"10.1109\/GLOCOM.2015.7417767"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Idita, A., Butnariu, V., Rosu, G., Trip, B., Boitan, A., and Baltag, O. (2018, January 4\u20136). Study of Shielding Effectiveness on Spurious Emissions of Information Systems by Means of Metallic and Carbon Powder Screens. Proceedings of the International Conference on Applied and Theoretical Electricity (ICATE), Craiova, Romania.","DOI":"10.1109\/ICATE.2018.8551420"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2639","DOI":"10.1587\/transcom.E96.B.2639","article-title":"Emission security limits for compromising emanations using electromagnetic emanation security channel analysis","volume":"96","author":"Lee","year":"2013","journal-title":"IEICE. Trans. Commun."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Tajima, K., Ishikawa, R., Mori, T., Suzuki, Y., and Takaya, K. (2017, January 4\u20137). A study on risk evaluation of countermeasure technique for preventing electromagnetic information leakage from ITE. Proceedings of the 2017 International Symposium on Electromagnetic Compatibility\u2014EMCEUROPE, Angers, France.","DOI":"10.1109\/EMCEurope.2017.8094753"},{"key":"ref_26","unstructured":"International Telecommunications Union (2015). Mitigation Methods Against Electromagnetic Security Threats, Telecommunication Standardization Sector of ITU."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Xie, C.H., Wang, T., Hao, X., Yang, M., Zhu, Y., and Li, Y. (2019). Localization and Frequency Identification of Large-Range Wide-Band Electromagnetic Interference Sourcesin Electromagnetic Imaging System. Electronics, 8.","DOI":"10.3390\/electronics8050499"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"403","DOI":"10.1080\/02726349208908322","article-title":"Time domain solution of electromagnetic problems","volume":"12","year":"1992","journal-title":"Electromagnetics"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Boitan, A., B\u0103tu\u015fic\u0103, R., Halunga, S., and Fratu, O. (2019). Electromagnetic Vulner abilities of LCDP rojectors. Proceedings of the 6th Conference on the Engineering of Computer Based Systems, Bucharest, Romania, 2\u20133 September 2019, University Politechnicaof Bucharest.","DOI":"10.1145\/3352700.3352722"},{"key":"ref_30","unstructured":"Kubiak, I. (2014). Computer Font Resistance to Electromagnetic Infiltration. The Research and Analysis Results, Publishing House of the Military University of Technology."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Kubiak, I., Boitan, A., and Halunga, S. (2020). Assessing the Security of TEMPEST Fonts against Electromagnetic Eavesdropping by Using Different Specialized Receivers. Appl. Sci., 10.","DOI":"10.3390\/app10082828"}],"container-title":["Symmetry"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-8994\/12\/11\/1908\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:34:54Z","timestamp":1760178894000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-8994\/12\/11\/1908"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,11,20]]},"references-count":31,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2020,11]]}},"alternative-id":["sym12111908"],"URL":"https:\/\/doi.org\/10.3390\/sym12111908","relation":{},"ISSN":["2073-8994"],"issn-type":[{"type":"electronic","value":"2073-8994"}],"subject":[],"published":{"date-parts":[[2020,11,20]]}}}