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Tony Ingesson, black/white photo.

Tony Ingesson

Associate Senior Lecturer

Tony Ingesson, black/white photo.

Clandestine Communications in Cyber-Denied Environments : Numbers stations and radio in the 21st century


  • Tony Ingesson
  • Magnus Andersson

Summary, in English

Both intelligence operatives and criminals have a constant need to be able to communicate clandestinely, circumventing surveillance efforts carried out by highly capable adversaries. The recent highly-publicized breaches of internet-based clandestine communications technology and targeted malware attacks, in combination with increasingly sophisticated methods for surveillance of internet traffic has arguably resulted in a cyber-denied environment. This paper employs a red-teaming approach to explore how clandestine communications can be structured using platforms that are physically separated from the internet and thus not vulnerable to internet-based surveillance or attacks. Recent developments in computer-based radio software can be combined with legacy radio technology to provide robust solutions for clandestine communications in a cyber-denied environment. Drawing on case studies from the Cold War, contemporary observations of clandestine radio networks in use today, and technical tests carried out by the authors, this paper stresses the importance for counterintelligence and law enforcement to be prepared for a potential shift in how clandestine communications are implemented by both hostile intelligence services and organized crime. Finally, the paper addresses the issue of proactively countering these techniques by presenting concrete methods for use by counterintelligence and law enforcement to detect radio-based clandestine communications and secure evidence.


  • Department of Political Science

Publishing year





Journal of Policing, Intelligence and Counter Terrorism

Document type

Journal article


Taylor & Francis


  • Political Science (excluding Public Administration Studies and Globalization Studies)


  • criminal intelligence
  • counterintelligence
  • numbers stations
  • clandestine communications
  • radio




  • Clandestine Communications: Old Technologies, New Opportunities


  • ISSN: 1833-5330