Signal Intelligence (SIGINT) refers to the collection, analysis, and interpretation of signals emitted by communication devices and electronic systems to obtain intelligence. As one of the most critical components of modern intelligence operations, SIGINT has become an integral part of national security strategies, particularly in today’s increasingly digital world.

SIGINT is generally categorized into two main branches:

• Electronic Intelligence (ELINT): Involves the interception and analysis of signals emitted by electronic devices. It provides information on the operational principles and capabilities of systems such as radars and missile guidance technologies.
• Communications Intelligence (COMINT): Entails the interception and evaluation of communication signals to gather insights into the activities and intentions of target actors.

Historical Background and Development

The significance of SIGINT became especially pronounced during World War II, due to the strategic use of radar and communication systems in military operations. Today, it is enhanced by advanced software and artificial intelligence-supported platforms, enabling more effective implementation. Information superiority is vital in military decision-making, and SIGINT serves as a key source for both strategic and tactical intelligence. Signals can be classified as friendly or hostile, and their origin can be identified and geolocated. For instance, by analyzing the deployment and functioning of radar and communication systems, it is possible to infer enemy movements and capabilities. Additionally, signal interception can yield crucial information regarding future offensive or defensive operations, including radio broadcasts in the region and potential adversarial elements.

SIGINT practices are primarily applied in the following three areas:

• Military Operations: Utilized to determine the movements, technologies, and strategic objectives of enemy forces.
• Cybersecurity: Aims to prevent attacks by monitoring the digital communications of threat actors.
• Aviation and Maritime Security: Signal collection from aircraft and vessels enables threat monitoring in international airspace and territorial waters.

Edward Snowden and the NSA Scandal

Edward Snowden, a former American intelligence contractor, disclosed extensive classified documents in 2013 regarding the global surveillance programs operated by the U.S. National Security Agency (NSA) and the United Kingdom’s Government Communications Headquarters (GCHQ). These revelations exposed the agencies' capabilities in monitoring phone conversations, collecting internet traffic, and harvesting the personal data of millions worldwide. Snowden's disclosures triggered global outrage and concern. Governments, civil society organizations, and individuals raised critical questions regarding privacy, state surveillance, and international relations. The NSA scandal prompted major reforms in SIGINT practices. Public demand for transparency increased, compelling governments to disclose more about their surveillance activities. Independent oversight bodies were established or empowered to monitor surveillance practices. Snowden’s revelations also underscored the importance of encryption technologies and spurred new research in the field of cybersecurity.

Signal Intelligence in Türkiye

Türkiye has made significant progress in SIGINT capabilities, particularly through advancements in its defense industry. National institutions such as TÜBİTAK, ASELSAN, and BAYKAR have been instrumental in developing indigenous and nationally integrated solutions to enhance electronic and signal intelligence competencies.