What Is Signals Intelligence?
Written by:
University of Tulsa
• Jan 15, 2025
U.S. national security doesn’t solely depend on military might. It also relies on the country’s ability to intercept, interpret, and disrupt the communications of its adversaries. This technology-focused form of intelligence gathering is called signals intelligence (SIGINT).
In the early to mid-20th century, SIGINT was primarily used in warfare to listen to wireless radio communications. As technology advanced, so did SIGINT.
Today, SIGINT is an integral part of cybersecurity, and it’s crucial to protecting countries across the world. Prospective professionals interested in SIGINT and information security should consider how they can prepare for this role through cybersecurity education and experience.
Types of Signals Intelligence
SIGINT is divided into three main fields. Each concerns a different type of information gathered from a different type of source.
Communications Intelligence
Communications intelligence (COMINT) involves intercepting interpersonal communication. This can include phone calls, emails, texts, and radio transmissions. In addition to figuring out what’s being communicated, COMINT professionals must also determine who’s communicating and where they’re located.
To accomplish these goals, COMINT professionals:
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Bypass cybersecurity measures
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Decode encrypted communications using cryptography and specialized software
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Scan multiple radio frequencies, especially when parties switch frequencies as a precaution
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Analyze voices and speech patterns to learn more about the communicating parties
In warfare, COMINT is often used to uncover an adversary’s plans, movements, or location. However, it’s also vital to identifying potential perpetrators of terror attacks and preventing mass casualty events.
Electronic Intelligence
Many electronics have nothing to do with communication. For example, radar systems, security sensors, and satellites all continuously record data. Electronic intelligence (ELINT) focuses on gathering intelligence from these sources.
ELINT can reveal a lot about a party, including the following:
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Capabilities
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Data used to make decisions
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Location
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Routines, procedures, and security protocols
This data can be used in multiple ways. First, ELINT is often used in surveillance and reconnaissance before military operations. It can also be used in cyber warfare—the same systems being monitored can often be disabled.
This can be done remotely or through drones, piloted aircraft, and signal jammers placed in strategic locations. Such measures can prevent the need to risk personnel, saving time, resources, and lives.
Foreign Instrumentation Sales Intelligence
Missiles, aircraft, boats, and other military equipment send information to other devices on dedicated networks. They might relay their speed, local weather conditions, and pictures from onboard cameras. Monitoring these device-to-device communications is called foreign instrumentation sales intelligence (FISINT).
FISINT can tell intelligence operatives a lot of the same information that they can learn through other forms of SIGINT. However, it can also provide technical data, such as:
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What kind of software different systems use
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Whether adversaries are testing new hardware
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Where hardware was purchased, stolen, or developed
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How many of a certain type of weapon are in enemy hands
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Where aircraft, sea vessels, and important logistical centers are located
This information can contribute to military operations or countermeasures. FISINT can also help operatives determine whether terrorist organizations or adversarial governments are trying to develop nuclear or chemical weapons.
Civil Liberties and National Security: The Use of Signals Intelligence in America
In the U.S., the use of signals intelligence is typically limited to matters of national security originating from foreign threats. Using SIGINT tactics on Americans is generally prohibited unless an individual or an organization is acting on behalf of a foreign entity.
These regulations are outlined in Presidential Policy Directive 28, an order issued by the White House in 2014. The directive also mandates that all SIGINT operations be authorized by a presidential directive or a similar order.
In 2022, the White House created the Data Protection Review Court to handle violations of intelligence-gathering procedures. Such safeguards are critical to protecting civil liberties and maintaining public trust.
Organizations Authorized to Use SIGINT
The U.S. government restricts SIGINT activities, so only certain federal organizations typically carry them out. The country’s leading SIGINT organization is the National Security Agency (NSA).
The NSA conducts intelligence operations to help elected officials and military leaders make informed decisions about warfare, counterterrorism, and national security. Other organizations that carry out SIGINT operations include the CIA and the intelligence divisions of each branch of the U.S. armed forces.
Collectively, this group of organizations and agencies makes up the U.S. Intelligence Community (IC). The FBI, Drug Enforcement Administration, and other law enforcement agencies are also members of the IC; because they largely focus on domestic affairs, they don’t carry out SIGINT operations. However, when they cooperate with agencies that do, they must adhere to guidelines set forth by presidential directives.
Prepare for a Career in Signals Intelligence
No matter what kind of data SIGINT operations acquire, the analysts who decide how to use it must be well versed in a wide range of fields and hold advanced cybersecurity training. This can prepare them for success in deciphering and anticipating threats through intelligence.
If you are interested in a career in cyber intelligence , consider the online Master of Science (M.S.) in Cyber Security at The University of Tulsa. Our program can hone your knowledge and skills in essential cybersecurity principles, including malware, information and network security, defensive cybersecurity, and more.
Explore our M.S. in Cyber Security today and find out how you can advance your career.
Recommended Readings
How to Become an Ethical Hacker
Cybersecurity Architect Job Description
What Does a Security Compliance Analyst Do?
Sources:
FBI, Executive Order 14086: Implementing Policies and Procedures
National Security Agency, Signals Intelligence (SIGINT) Overview
Office of the Director of National Intelligence, Members of the IC
