Electronic Warfare and Security
Electronic warfare and security is the domain where electromagnetic compatibility principles meet defense, national security, and the protection of essential systems. Conventional EMC engineering treats electromagnetic energy as an accidental nuisance to be limited and tolerated. Here the same physics is approached deliberately: electromagnetic energy becomes a weapon to be projected, a threat to be withstood, or a covert channel through which sensitive information may leak. The engineering toolkit is largely shared with mainstream EMC, including shielding, filtering, grounding, and emission and immunity measurement, but the threat model is adversarial rather than statistical.
This category covers four closely related disciplines: the intentional disruption and protection of electronic systems, the prevention of information leakage through compromising emanations, the hardening of critical national infrastructure against electromagnetic threats, and the electromagnetic dimension of cybersecurity. A radar operator denying an adversary the use of the spectrum, an accreditation engineer suppressing the faint signal that a display radiates, and a hardware-security analyst extracting a cryptographic key from a smart card's stray emissions are all working different faces of the same problem: controlling electromagnetic energy that someone else would prefer to exploit.
The Electronic Warfare Framework
Electronic warfare is conventionally divided into three functions. Electronic attack (EA) uses electromagnetic or directed energy to degrade, neutralize, or deceive an adversary's use of the spectrum, encompassing jamming, spoofing, and high-power electromagnetic effects. Electronic protection (EP) preserves friendly use of the spectrum in the presence of such attacks, through measures such as frequency agility, spread-spectrum and low-probability-of-intercept waveforms, antenna nulling, and emission control. Electronic support (ES, also called electronic warfare support) passively searches for, intercepts, identifies, and geolocates radiated emissions to build situational awareness and to cue the other two functions. These categories are interdependent: support data drives attack decisions, and protection assumes that an adversary is conducting support and attack of its own.
The two most familiar forms of electronic attack are jamming and spoofing, and the contrast between them is instructive. Jamming is denial: a transmitter floods a band with noise or a tailored signal so that a receiver can no longer recover the information it wants, as when a barrage or spot jammer raises the noise floor against a communications link or a radar. Spoofing is deception: the attacker injects a counterfeit but plausible signal so that the victim acts on false data. Global navigation satellite system (GNSS) spoofing is the canonical example. Because civilian GPS signals are unencrypted and extremely weak at the surface, a spoofer can transmit counterfeit satellite signals that gradually capture a receiver's tracking loops and walk its computed position or time away from the truth, diverting a drone or vessel without any obvious loss of lock. Jamming announces itself by degrading service; well-executed spoofing is dangerous precisely because the victim may never know it occurred.
Compromising Emanations and TEMPEST
Information security depends not only on cryptography but on the physical confinement of the signals that carry sensitive data. Almost every device that processes information unintentionally radiates and conducts some representation of that information through stray electromagnetic emissions, power-line ripple, and acoustic or mechanical vibration. These compromising emanations can, in principle, be intercepted and reconstructed at a distance, a threat made public in 1985 when researcher Wim van Eck demonstrated that the image on a video display could be recovered from its radiated emissions using modest equipment, an exploit now widely known as van Eck phreaking.
TEMPEST is the umbrella term for the study and control of compromising emanations and for the standards that govern shielding, testing, and accreditation of equipment and facilities that handle classified information. The discipline rests on principles such as red/black separation, the strict isolation of circuits and cabling that carry plaintext (red) from those that carry encrypted or non-sensitive signals (black), together with shielding, filtering of every penetration of a secure boundary, and zoning that relates the required protection to the distance an adversary could plausibly reach. In the United States, equipment-level test requirements have historically been specified in NSTISSAM TEMPEST/1-92, the NSA's laboratory test standard for compromising emanations; detailed limits remain classified, and certified products are procured under defense acquisition rules such as DFARS 252.239-7000. The countermeasures are recognizably EMC techniques, but the acceptance criterion is the absence of recoverable information rather than compliance with a published emission limit.
Intentional Electromagnetic Interference and Infrastructure
Beyond communications and intelligence, electromagnetic energy is a recognized threat to the physical infrastructure that modern society depends upon. Intentional electromagnetic interference (IEMI) is the deliberate generation of electromagnetic energy to disrupt, damage, or destroy electronic equipment, ranging from compact, commercially feasible radio-frequency sources to large high-power electromagnetic (HPEM) and high-altitude electromagnetic pulse (HEMP) effects. The IEC has characterized these environments in its 61000-2 series, including IEC 61000-2-13 for radiated and conducted HPEM environments and IEC 61000-2-9 for the radiated HEMP environment, which provide representative waveforms that protection engineers design against.
The consequences are not abstract. Power grids, telecommunications networks, water and wastewater control, transportation signaling, financial settlement systems, and emergency services all rely on dense, interconnected electronics whose long cable runs and exposed antennas make efficient coupling paths for electromagnetic energy. Protecting them borrows directly from the EMC hardening playbook, including shielded enclosures, surge and transient protection coordinated across entry points, filtered penetrations, and resilient grounding, but applies it against a threat that is intentional, may be concentrated in time and space, and may be aimed at the weakest single point rather than the average case.
Electromagnetic Dimensions of Cybersecurity
The boundary between electromagnetic engineering and cybersecurity has largely dissolved at the hardware level. Side-channel attacks exploit the fact that a device's power consumption and electromagnetic emissions are correlated with the data it processes. Simple and differential power analysis (SPA and DPA) recover secret keys by statistically analyzing power traces collected while a cryptographic operation runs; their electromagnetic counterparts, simple and differential electromagnetic analysis (SEMA and DEMA), do the same using a near-field probe and require no direct electrical contact. Related techniques, including correlation power analysis and template attacks, have repeatedly extracted keys from smart cards, embedded controllers, and other tamper-resistant devices.
Fault injection is the active complement to these passive attacks: a precisely timed voltage glitch, clock disturbance, or electromagnetic pulse can corrupt a single instruction or computation, causing a device to skip a security check or leak intermediate values. Defending against this family of threats unites EMC and security practice, drawing on emission reduction and shielding to shrink the side channel, alongside algorithmic countermeasures such as masking, hiding, and constant-time execution. The same discipline informs the protection of wireless interfaces, hardware roots of trust, and the integrity of the supply chain through which components reach a finished system.
Topics in This Category
Summary
Electronic warfare and security applies the physics and engineering of electromagnetic compatibility to adversarial problems. Where mainstream EMC limits accidental interference and assures coexistence, the topics gathered here address energy that is deliberately projected to deny or deceive, emissions that must be confined to keep secrets, infrastructure that must survive intentional electromagnetic stress, and the stray signals that quietly betray cryptographic keys. The countermeasures, including shielding, filtering, grounding, emission control, and disciplined measurement, are the familiar tools of the field, but they are deployed against an intelligent opponent rather than a random environment. The subtopics that follow examine attack and protection, emissions security, infrastructure resilience, and electromagnetic cybersecurity in greater depth.