Emsec - – Protection for electromagnetic emanations

– Protection for
electromagnetic emanations

EMSEC – How can we protect ourselves against electromagnetic emanations?

All electric devices emit unintentional electromagnetic signals. EMSEC (emission security) is a construct that analyzes the risk if such electromagnetic signals gets picked up deliberately by special listening devices, or unintentionally between two devices. If such signals contain confidential information that can be interpreted by unauthorized persons, this can thus lead to devastating consequences. Such signals are furthermore defined as electromagnetic emanations (see below).

Within the Armed Forces and its associated industries, safe EMSEC systems therefore are one of many crucial steps to ensure both emission security and IT security as a whole. As more businesses realize the threats and risks that come with modern information society, the demand for EMSEC protection around several industries are increasing notably.

For more than 30 years, Fibersystem’s innovative developers have created products and services to protect businesses from unauthorized infringement. In the following guide we will sort out the concept of EMSEC and electromagnetic emanations more in detail and also explain how we can help more businesses to safer operations.

EMSEC – The basics, what is it?

To understand EMSEC further there are a few more definitions that needs to be sorted out. These are first and foremost TEMPEST and electromagnetic emanations (also named leaking emanations).


Tempest is a NATO-certification that includes both protection against electromagnetic emanations and methods to spy upon others.

Electromagnetic emanations (leaking emanations)

Electromagnetic emanations refer to the electromagnetic radiations that all electric devices emit. If such radiations furthermore are disclosed, there is a risk that information that the radiations carry may leak out to unauthorized persons.

Generally we can also distinguish between two types of sources within electromagnetic emanations. These are:

  1. Information source: The information that the electronic radiations carry
  2. Physical source: The electric component/s that has generated the radiations
Depending on the type of 1) information source and 2) physical source, different forms of electromagnetic emanations are furthermore defined. Below are four common forms of electromagnetic emanations to be mindful of.

Four common forms of electromagnetic emanations

Electromagnetic emanations through radio

Electromagnetic emanations through radio is an extra treacherous form of electromagnetic emanations that can occur between two devices that carry radio transmitters – such as mobile phones and radios. What makes electromagnetic emanations through radio particularly vulnerable is also that it can occur unintentionally between two electric components. It thus does not need to be an active spy who tries to reveal confidential information for electromagnetic emanations to occur here. Electromagnetic emanations through radio can also carry information over very large distances.

Electromagnetic crosstalks

Electromagnetic crosstalks is an umbrella term that describe when signals are being transmitted by means of an electromagnetic clutch – such as can unintentionally happen with electromagnetic emanations through radio. The signals transmitted via electromagnetic crosstalks often come in a more or less distorted form, but considering that confidential information might get carried a serious risk for electromagnetic emanations still exist.

Electromagnetic emanations through keyboards

Electromagnetic emanations through keyboards is a type of electromagnetic enemation that can occur when information is being transmitted from for example a keyboard to a computer.

Electromagnetic emanations through video

Electromagnetic emanations through video is another form of electromagnetic emanations that can occur when information is being transmitted from a computer to a computer screen.

Generally, any type of electromagnetic emanations can also occur and take form in two different ways. Roughly categorized this is through metallic line wires or by a fully aerial connection.

Connection through metallic line wires

Connection through metallic line wires mainly occurs and takes form in:

  • Telephone wires and power lines
  • Conduit pipes
  • Other pipes and materials of concrete steele etc.

Connection through metallic line wires usually occur at frequencies < 30 MHz. Such short-wave frequencies (also called high-frequency wavelengths) gives, with good conditions, audibility over very long distances.

Aerial connections

An aerial connection instead occurs if linkages take form between two transmitting aerials. Frequencies are here limited to higher frequencies > 30 MHz. Electromagnetic crosstalks (which may create electromagnetic emanations through radio) is an example of a fully aerial connection.

EMSEC – the basics. How can we protect ourselves?

To improve emission security and minimize the risk for electromagnetic emanations, one can take several actions. The various mechanisms can briefly be categorized as below:

  • Special equipment against electromagnetic emanations

Through special equipment one can either eliminate (Class 1 – U1) or limit (Class 2 – U2 or class 3 – U3) the risk for electromagnetic emanations. On Fibersystem we offer protection against electromagnetic emanations, Class 1 (U1).

  • Special rooms or cabinets to improve emission security

If equipment that carry sensitive information not is provided with its own protection against electromagnetic emanations, one can instead place it in a special room or in a cabinet. Such rooms contain walls that prevent electromagnetic signals to reach the outside world. Just as with equipment against electromagnetic emanations there are different degrees of such protection, where Security Class 1 (SS1) implies elimination of electromagnetic emanations and Sercurity Class 2 (SS2) implies limitation of it. Fibersystem has cabinets with protection, Security Class 1 (SS1).

  • Use of distance

By taking advantage of that radio frequency signals decrease with increased distance, one can use distance as a form of protection. By using natural forms of protection one can also reduce the risk of electromagnetic emanations. Some basic guidelines to improve emission security is for example that:

  • Sensitive equipment should be placed in the inner part of the building.
  • Sensitive equipment should be placed as close to the ground as possible, preferably under. Sensitive equipment can also be placed close to walls.
  • Do not place equipment that carry sensitive information directly in front of a window.

Please note that the above not should be considered as a substitute for protection, but rather as an additional precaution.

EMSEC – the basics. Why do we need to protect ourselves?

Electromagnetic emanations has for a long time been a strong threat against IT security. Historically, whole nations were them who had the capacity to carry out electromagnetic emanations and nations and their surrounding authorities therefore naturally became the prime target. As technology has become both cheaper and more available, it is though reasonable to assume that civil organizations can engage in reconnaissance and that their targets thus may be civil. Today, there are examples of commercial businesses that have begun to take steps to protect themselves against
electromagnetic emanations.


Welcome to contact us at Fibersystem if you want to know more about how we can help your business to improve emission security. We are leading in fiber optic transmission and IT security and develop tailor-made and safe products that are used globally – for both large and small organizations.

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