This article is a subset article in a series under intelligence collection management. Intelligence Collection Management is the process of managing and organizing the collection of intelligence information from various sources For a hierarchical list of articles, see the intelligence cycle management hierarchy. This article is at the top level of a series of articles about Intelligence Cycle Management

SIGINT is a contraction of SIGnals INTelligence, which is a intelligence-gathering by interception of signals, whether between people (i. In Traditional grammar, a contraction is the formation of a new Word from one or more individual words Intelligence Gathering Disciplines HUMINT Human Intelligence - gathered from a person on the ground e. , COMINT or communications intelligence) or between machines (i. e. , ELINT or electronic intelligence), or mixtures of the two. As sensitive information is often encrypted, SIGINT often involves the use of cryptanalysis. Cryptanalysis (from the Greek kryptós, "hidden" and analýein, "to loosen" or "to untie" is the study of methods for However, traffic analysis—the study of who is signalling whom and in what quantity—can often produce valuable information, even when the messages themselves cannot be decrypted. See SIGINT by Alliances, Nations and Industries for the organization of SIGINT activities, and SIGINT Operational Platforms by Nation for current collection systems, and SIGINT in Modern History from World War I to the present. World War I (abbreviated WWI; also known as the First World War, the Great War, and the War to End All

As a means of collecting intelligence, SIGINT is a subset of intelligence collection management, which, in turn, is a subset of intelligence cycle management. Intelligence Collection Management is the process of managing and organizing the collection of intelligence information from various sources This article is at the top level of a series of articles about Intelligence Cycle Management

Intercepting written but encrypted communications, and extracting information, probably did not wait long after the development of writing. A simple encryption system, for example, is the Caesar cipher. In Cryptography, a Caesar cipher, also known as a Caesar's cipher, the shift cipher, Caesar's code or Caesar shift, is one of the Electronic interception appeared as early as 1900, during the Boer War. The Boers had captured some British radios, and, since the British were the only people transmitting at the time, had signals rather obvious to intercept. ^[1]

More technical definitions of SIGINT and its branches

In the United States and other nations involved with NATO, SIGINT is defined as:^[2]

• A category of intelligence comprising either individually or in combination all communications intelligence (COMINT), electronic intelligence (ELINT), and foreign instrumentation signals intelligence, however transmitted. The United States of America —commonly referred to as the The North Atlantic Treaty

• Intelligence derived from communications, electronic, and foreign instrumentation signals. "

The JCS definition may overemphasize "foreign instrumentation signals". That part should be considered in combination with MASINT, which is closely linked to foreign instrumentation such as telemetry or radionavigation. Measurement and Signature Intelligence, or MASINT, refers to intelligence gathering activities that bring together disparate elements that do not fit within the Telemetry (synonymous with Telematics) is a Technology that allows the remote measurement and reporting of Information of interest to the system designer Radio navigation or radionavigation is the application of Radio frequencies to determining a position on the Earth. An ELINT sensor may find a radar, and then cue (i. Measurement and Signature Intelligence, or MASINT, refers to intelligence gathering activities that bring together disparate elements that do not fit within the e. , guide) a COMINT sensor for listening in on the talk between the radar and its remote users. A nonspecific SIGINT sensor can cue a Frequency Domain MASINT sensor that can help identify the purpose of the signal. Measurement and Signature Intelligence, or MASINT, refers to intelligence gathering activities that bring together disparate elements that do not fit within the If MASINT cannot identify the signal, then the intelligence organization may task an IMINT aircraft or satellite to take a picture of the source, so photointerpreters can try to understand its functions. IMINT, short for IM agery INT elligence is an intelligence gathering discipline which collects information via satellite and Aerial photography

Being a broad field, SIGINT has many sub-disciplines. The two main ones are COMmunications INTelligence (COMINT) and ELectronic INTelligence (ELINT). There are, however, some techniques that can apply to either branch, as well as to assist FISINT or MASINT. FISINT stands for F oreign I nstrumentation S ignals INT elligence Measurement and Signature Intelligence, or MASINT, refers to intelligence gathering activities that bring together disparate elements that do not fit within the

Disciplines Shared across the Branches

An excellent Australian analysis of how the pieces came together, from targeting to physical destruction of radars, in Desert Storm was written by Carlo Kopp. ^[3]

Targeting

A collection system has to know to look for a particular signal. "System", in this context, has several nuances. Targeting is an output of the process of developing collection requirements:

"1. An intelligence need considered in the allocation of intelligence resources. Within the Department of Defense, these collection requirements fulfill the essential elements of information and other intelligence needs of a commander, or an agency.

"2. An established intelligence need, validated against the appropriate allocation of intelligence resources (as a requirement) to fulfill the essential elements of information and other intelligence needs of an intelligence consumer. "^[2]

Need for multiple, coordinated receivers

First, even with a geographically fixed target, atmospheric conditions, sunspots, the target's transmission schedule and antenna characteristics, and other factors, mean that a given signal intercept sensor is not guaranteed to be able to "hear" the signal of interest, even if the opponent made no attempt to make the signal hard to intercept. A sunspot is a region on the Sun 's surface ( Photosphere) that is marked by intense magnetic activity which inhibits Convection, forming Among the most basic countermeasures against interception is frequent changing of frequency, and other transmission characteristics such as polarization. Frequency is a measure of the number of occurrences of a repeating event per unit Time. Polarization ( ''Brit'' polarisation) is a property of Waves that describes the orientation of their oscillations Such countermeasures mean that an intercept aircraft could not get off the ground if it had to carry antennas and receivers for every possible frequency and signal type.

Second, locating the transmitter's position is usually part of SIGINT. Triangulation and more sophisticated radiolocation techniques, such as time of arrival methods, require multiple receiving points at different locations. In Trigonometry and Geometry, triangulation is the process of determining the location of a point by measuring angles to it from known points at either Time of Arrival (ToA also named Time of Flight (ToF which both means the travel time of a radio signal from a single transmitter to a remote single receiver These receivers send location-relevant information to a central point, or perhaps to a distributed system in which all participate, such that the information can be correlated and a location computed.

Intercept management

Modern SIGINT systems, therefore, have substantial communications among intercept platforms. Even if some platforms are clandestine, there is a broadcast of information telling them where and how to look for signals. ^[4] A U. S. targeting system under development in the late 1990s, PSTS, constantly sends out information that helps the interceptors properly aim their antennas and tune their receivers. Larger intercept aircraft, such as the EP-3 or RC-135, have the onboard capability to do some target analysis and planning, but others, such as the RC-21 GUARDRAIL, are completely under ground direction. The Lockheed EP-3E ARIES II is the signals reconnaissance version of the P-3C Orion, operated by the United States Navy. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout GUARDRAIL aircraft are fairly small, and usually work in units of three to cover a tactical SIGINT requirement, where the larger aircraft tend to be assigned strategic/national missions.

In other words, before the detailed process of targeting begins, someone has to decide there is a value in collecting information about something. While it would be possible to direct signals intelligence collection at a major sports event, the systems would capture a great deal of noise, news signals, and perhaps announcements in the stadium. If, however, an antiterrorist organization believed that a small group would be trying to coordinate their efforts, using short-range unlicensed radios, at the event, SIGINT targeting of radios of that type would be reasonable. Targeting would not know where in the stadium the radios might be, or the exact frequency they are using; those are the functions of subsequent steps such as signal detection and direction finding.

Once the decision to target is made, the various interception points need to cooperate, since resources are limited. A Knowing what interception equipment to use becomes easier when a target country buys its radars and radios from known manufacturers, or is given them as part of foreign military aid. National intelligence services keep libraries of devices manufactured by their own country and others, and then use a variety of techniques to learn what equipment is acquired by a given country.

See "The Target - The Iraqi IADS" for a discussion on how the Iraqi air defense system was targeted in 1991. ^[3] Note the different requirement for search radar and for the different area defense and point defense missile systems, and how these guided the Suppression of Enemy Air Defense (SEAD) attacks on the radars, command centers, and missiles. SEAD (pronounced see-add or seed or Suppression of Enemy Air Defences, also known as " Wild Weasels quot and "Iron Hand" operations in the USA are

Knowledge of physics and electronic engineering further narrows the problem of what types of equipment might be in use. An intelligence aircraft flying well outside the borders of another country will listen for long-range search radars, not short-range fire control radars that would be used by a mobile air defense. Soldiers scouting the front lines of another army know that the other side will be using radios that must be portable and not have huge antennas.

Signal detection

Whether a signal is human communications (e. g. , a radio), the intelligence collection specialists have to know it exists. If the targeting function described above learns that a country has a radar that operates in a certain frequency range, the first step is to use a sensitive receiver, with one or more antennas that listen in every direction, to find an area where such a radar is operating. Once the radar is known to be in the area, the next step is to find its location.

Simplified spectrum analyzer display of superheterodyned,amplitude modulated signals

If operators know the probable frequencies of transmissions of interest, they may use a set of receivers, preset to the frequencies of interest. A spectrum analyzer or spectral analyzer is a device used to examine the spectral composition of some electrical, acoustic, or optical In Electronics, the superheterodyne receiver (also known by its full name the supersonic heterodyne receiver, or by the abbreviated form superhet) is a Amplitude modulation ( AM) is a technique used in electronic communication most commonly for transmitting information via a Radio Carrier wave These are the frequency (horizontal axis) versus power (vertical axis) produced at the transmitter, before any filtering of signals that do not add to the information being transmitted. Received energy on a particular frequency may start a recorder, and alert a human to listen to the signals if they are intelligible (i. e. , COMINT). If the frequency is not known, the operators may look for power on primary or sideband frequencies using a spectrum analyzer signals] Information from the spectrum analyzer is then used to tune receivers to signals of interest. In Radio communications a sideband is a band of Frequencies higher than or lower than the Carrier frequency, containing power as a result of A spectrum analyzer or spectral analyzer is a device used to examine the spectral composition of some electrical, acoustic, or optical For example, in this simplified spectrum, the actual information is at 800 kHz and 1. 2 MHz.

Hypothetical displays from four spectrum analyzers connected to directional antennas. The transmitter is at bearing 090 degrees

Real-world transmitters and receivers usually are directional. In the figure to the left, assume that each display is connected to a spectrum analyzer connected to a directional antenna aimed in the indicated direction.

Countermeasures to interception

Spread-spectrum communications is an electronic counter-countermeasures (ECCM) technique to defeat looking for particular frequencies. Electronic counter-countermeasures (ECCM describes a variety of practices which attempt to reduce or eliminate the effect of Electronic countermeasures (ECM on electronic Spectrum analysis can be used in a different ECCM way, to identify frequencies not being jammed or not in use.

Direction-finding

Main article: Radio_direction_finding

The earliest, and still common, means of direction finding is to use directional antennas as goniometers, so that a line can be drawn from the receiver through the position of the signal of interest. Direction finding (DF refers to the establishment of the direction from which a received signal was transmitted Direction finding (DF refers to the establishment of the direction from which a received signal was transmitted A goniometer is an instrument that either measures angle or allows an object to be rotated to a precise angular position See HF/DF. High frequency direction finder is usually known by its Acronym HF/DF, pronounced Huff-Duff. Knowing the compass bearing, from a single point, to the transmitter does not locate it. Where the bearings from multiple points, using goniometry, are plotted on a map, the transmitter will be located at the point where the bearings intersect. This is the simplest case; a target may try to confuse listeners by having multiple transmitters, giving the same signal from different locations, switching on and off in a pattern known to their user but apparently random to the listener.

Individual directional antennas have to be manually or automatically turned to find the signal direction, which may be too slow when the signal is of short duration. One alternative is to use the Wullenweber array technique. The Wullenweber (the original name introduced by Dr Hans Rindfleisch was Wullenwe' v' er is a type of Circularly Disposed Antenna Array (CDAA sometimes referred to as a Circularly

AN/FLR-9 Wullenweber antenna array of the Bundesnachrichtendienst near Augsburg, Germany

In this method, several concentric rings of antenna elements simultaneously receive the signal, so that the best bearing will ideally be clearly on a single antenna or a small set. The AN /FLR-9 is a type of very large circular " Wullenweber " antenna array built at many locations during the Cold war for HF/DF The Wullenweber (the original name introduced by Dr Hans Rindfleisch was Wullenwe' v' er is a type of Circularly Disposed Antenna Array (CDAA sometimes referred to as a Circularly The Bundesnachrichtendienst ( Federal Intelligence Service, BND is the foreign Intelligence agency of the German government under the control of the Augsburg is an independent City in the south-west of Bavaria. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. Wullenweber arrays for high-frequency signals are enormous, referred to as "elephant cages" by their users.

An alternative technique to tunable directional antennas, or large omnidirectional arrays such as the Wullenweber, is to measure the time of arrival of the signal at multiple points, the points using GPS or a similar method to have precise time synchronization. Time of Arrival (ToA also named Time of Flight (ToF which both means the travel time of a radio signal from a single transmitter to a remote single receiver Basic concept of GPS operation A GPS receiver calculates its position by carefully timing the signals sent by the constellation of GPS Satellites high above the Earth The points at which the receivers can be placed can be on ground stations, ships, aircraft, or satellites, giving great flexibility.

Since modern weapons can home in on and attack transmitters, the antennas of a military unit frequently are a hopefully safe distance from the user of the transmitter.

Traffic analysis

Main article: Traffic analysis

When locations are known, usage patterns may emerge, and inferences drawn. Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in Communication. Traffic analysis is the discipline of drawing patterns from information flow among a set of senders and receivers, whether those senders and receivers are designated by location determined through direction finding, by addressee and sender identifications in the message, or even MASINT techniques for "fingerprinting" transmitters or operators. Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in Communication. Direction finding (DF refers to the establishment of the direction from which a received signal was transmitted Measurement and Signature Intelligence, or MASINT, refers to intelligence gathering activities that bring together disparate elements that do not fit within the Message content, other than the sender and receiver, is not necessary to do traffic analysis, although more information can be helpful.

For example, if a certain type of radio is known to be used only by tank units, even if the position is not precisely determined by direction finding, it may be assumed that a tank unit is in the general area of the signal. Of course, the owner of the transmitter can assume someone is listening, so might set up tank radios in an area where he wants the other side to believe he has actual tanks. As part of Operation Quicksilver, part of the deception plan for the invasion of Europe at the Battle of Normandy, radio transmissions simulated the headquarters and subordinate units of the fictitious First United States Army Group (FUSAG), commanded by George S. Patton, to make the German defense think that the main invasion was to come at another location. In World War II, Operation Quicksilver ( Allies, 1944) was a sub-plan of Operation Fortitude, the 1944 Deception plan designed to induce Deception (also called beguilement or subterfuge) is the act of convincing another to believe Information that is not true or not the whole truth as in First United States Army Group was a fictitious Army Group invented by the Allies in World War II prior to D-Day, as part of Operation Quicksilver For the 19th century Scottish jurist/politician see George Patton Lord Glenalmond. In like manner, fake radio transmissions from Japanese aircraft carriers, before the Battle of Pearl Harbor, were made from Japanese local waters, while the attacking ships moved under strict radio silence. The attack on Pearl Harbor (or Hawaii Operation, as it was called by the Imperial General Headquarters) was a surprise Military strike conducted by

Traffic analysis need not focus on human communications. For example, if the sequence of a radar signal, followed by an exchange of targeting data and a confirmation, followed by observation of artillery fire, this may identify an automated counterbattery system. A radio signal that triggers navigational beacons could be a landing aid system for an airstrip or helicopter pad that is intended to be low-profile.

Patterns do emerge. Knowing a radio signal, with certain characteristics, originating from a fixed headquarters may be strongly suggestive that a particular unit will soon move out of its regular base. The contents of the message need not be known to infer the movement.

There is an art as well as science of traffic analysis. Expert analysts develop a sense for what is real and what is deceptive. Harry Kidder, for example, was one of the star cryptanalysts of World War II, a star hidden behind the secret curtain of SIGINT. ^[5]

Electronic Order of Battle

Generating an Electronic order of battle (EOB) requires identifying SIGINT emitters in an area of interest, determining their geographic location or range of mobility, characterizing their signals, and, where possible, determining their role in the broader organizational order of battle. An order of battle was in its original form during the European period of Medieval warfare the order in which troops were positioned relative to the position of the Army commander EOB covers both COMINT and ELINT. ^[6] The Defense Intelligence Agency maintains an EOB by location. The Joint Spectrum Center (JSC) of the Defense Information Systems Agency supplements this location database with five more technical databases:

1. FRRS: Frequency Resource Record System
2. BEI: Background Environment Information
3. SCS: Spectrum Certification System
4. EC/S: Equipment Characteristics/Space
5. TACDB: platform lists, sorted by nomenclature, which contain links to the C-E equipment complement of each platform, with links to the parametric data for each piece of equipment, mlitary unit lists and their subordinate units with equipment used by each unit. The Defense Information Systems Agency (DISA formerly known as the Defense Communications Agency) is a combat support agency of the United States Department of Defense

EOB and related data flow

For example, several voice transmitters might be identified as the command net (i. e. , top commander and direct reports) in a tank battalion or tank-heavy task force. Another set of transmitters might identify the logistic net for that same unit. An inventory of ELINT sources might identify the medium- and long-range counter-artillery radars in a given area,

SIGINT units will identify changes in the EOB, which might indicate enemy unit movement, changes in command relationships, and increases or decreases in capability. Radar MASINT is one of the subdisciplines of Measurement and Signature Intelligence (MASINT and refers to intelligence gathering activities that bring together disparate Radar MASINT is one of the subdisciplines of Measurement and Signature Intelligence (MASINT and refers to intelligence gathering activities that bring together disparate

Using the COMINT gathering method enables the intelligence officer to produce an electronic order of battle by traffic analysis and content analysis among several enemy units. For example, if the following messages were intercepted:

1. U1 from U2, requesting permission to proceed to checkpoint X.
2. U2 from U1, approved. please report at arrival.
3. (20 minutes later) U1 from U2, all vehicles have arrived to checkpoint X.

This sequence shows that there are two units in the battlefield, unit 1 is mobile, while unit 2 is in a higher hierarchical level, perhaps a command post. One can also understand that unit 1 moved from one point to another which are distant from each 20 minutes with a vehicle. If these are regular reports over a period of time, they might reveal a patrol pattern. Direction-finding and Radiofrequency MASINT could help confirm that the traffic is not deception. Radiofrequency MASINT is one of the six major disciplines generally accepted to make up the field of Measurement and Signature Intelligence (MASINT with due regard that the

The EOB buildup process is divided as following:

• Signal separation
• Measurements optimization
• Data Fusion
• Networks build-up

Separation of the intercepted spectrum and the signals intercepted from each sensors must take place in an extremely small period of time, in order to separate the deferent signals to different transmitters in the battlefield. The complexity of the separation process depends on the complexity of the transmission methods (e. g. , hopping or Time division multiple access (TDMA)). Frequency-hopping spread spectrum ( FHSS) is a method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using This article is about the medium access technology The name "TDMA" is also commonly used in the United States to refer to D-AMPS, which is a mobile telephone

By gathering and clustering data from each sensor, the measurements of the direction of signals can be optimized and get much more accurate then the basic measurements of a standard direction finding sensor. Direction finding (DF refers to the establishment of the direction from which a received signal was transmitted ^[7] By calculating larger samples of the sensor's output data in near real-time, together with historical information of signals, better results are achieved.

Data fusion correlates data samples from different frequencies from the same sensor, "same" being confirmed by direction finding or radiofrequency MASINT. Direction finding (DF refers to the establishment of the direction from which a received signal was transmitted Radiofrequency MASINT is one of the six major disciplines generally accepted to make up the field of Measurement and Signature Intelligence (MASINT with due regard that the If an emitter is mobile, direction finding, other than discovering a repetitive pattern of movement, is of limited value in determining if a sensor is unique. MASINT then becomes more informative, as individual transmitters and antennas may have unique sidelobes, unintentional radiation, pulse timing, etc.

Network build-up among between each emitter (communication transmitter) to another enables creation of the communications flows of a battlefield. ^[8]

COMINT

COMINT (Communications Intelligence) is a sub-category of SIGINT that engages in dealing with messages or voice information derived from the interception of foreign communications. It should be noted that COMINT is commonly referred to as SIGINT, which can cause confusion when talking about the broader intelligence disciplines. The US Joint Chiefs of Staff defines it as "Technical information and intelligence derived from foreign communications by other than the intended recipients". ^[2]

COMINT, which is defined to be communications among people, will reveal some or all of the following:

1. Who is transmitting and or where they are located. If the transmitter is moving, the report may give a plot of the signal against location.
2. If known, the organizational function of the transmitter
3. The time and duration of transmission, and the schedule if it is a periodic transmission
4. The frequencies and other technical characteristics of their transmission
5. If the transmission is encrypted or not, and if it can be decrypted. If it is possible to intercept either an originally transmitted cleartext or obtain it through cryptanalysis, the language of the communication and a translation (when needed)
6. The addresses, if the signal is not a general broadcast and if addresses are retrievable from the message. These stations may also be COMINT (e. g. , a confirmation of the message or a response message), ELINT (e. g. , a navigation beacon being activated) or both. Rather than, or in addition to, an address or other identifier, there may be information on the location and signal characteristics of the responder

Voice interception

A basic COMINT technique is to listen for voice communications, usually over radio but possibly "leaking" from telephones or from wiretaps. If the voice communications are encrypted, the encryption first must be solved through a process of introelectric diagram in order to listen to the conversation, although traffic analysis (q. v. ) may give information simply because one station is sending to another in a radial pattern. It is important to check for various cross sections of conversation. It is equally important to make sure that you have the correct x pattern in relation to the a2 pattern. These can be found by using the SIGINT set given to all Naval communications officers and enlisted personnel with direct access to SIGINT communications.

Obviously, the interceptor must understand the language being spoken. In the Second World War, the United States used volunteer communicators known as code talkers, who used languages such as Navajo, Comanche and Choctaw, which would be understood by few people, even in the U. Navajo (sometimes spelled Navaho) or Diné, (means The People in Navajo) refers or relates to the Navajo people, currently The Comanche are a Native American ethnic group whose range (the Comancheria) consisted of present-day eastern New Mexico, southern Colorado The Choctaw are a Native American people originally from the Southeastern United States ( Mississippi, Alabama, and Louisiana) S. , who did not grow up speaking the language. Even within these uncommon languages, the code talkers used specialized codes, so a "butterfly" might be a specific Japanese aircraft. British forces made more limited use of Welsh speakers for the additional protection. Welsh ( cy Cymraeg or cy y Gymraeg, kəmˈrɑːɨɡ and {{IPA|[ə ɡəmˈrɑːɨɡ]}}, is a member of the Brythonic branch of Celtic

While modern electronic encryption does away with the need for armies to use obscure languages, it is certainly possible that guerilla groups might use rare dialects that few outside their ethnic group would understand.

Text interception

Not all communication is in voice. Morse code interception was once very important, but Morse code telegraphy is now obsolescent in the western world, although possibly used by special operations forces. Morse code is a Character encoding for transmitting telegraphic information using standardized sequences of short and long elements to represent the letters numerals Such forces, however, now have portable cryptographic equipment. Morse code is still used by military forces of former Soviet Union countries.

Specialists scan radio frequencies for character sequences (e. g. , electronic mail) and facsimile.

Signaling channel interception

A given digital communications link can carry thousands or millions of voice communications, especially in developed countries. Without addressing the legality of such actions, the problem of identifying which channel contains which conversation becomes much simpler when the first thing intercepted is the signaling channel that carries information to set up telephone calls. In civilian and many military use, this channel will carry messages in Signaling System 7 protocols. Signaling System #7 (SS7 is a set of Telephony signaling protocols which are used to set up most of the world's Public switched telephone network telephone

Retrospective analysis of telephone calls can be made from call detail records (CDR) used for billing the calls. A Call Detail Record (CDR is the computer record produced by a Telephone exchange containing details of a call that passed through it

Monitoring friendly communications

More a part of communications security than true intelligence collection, SIGINT units still may have the responsibility of monitoring one's own communications or other electronic emissions, to avoid providing intelligence to the enemy. For example, a security monitor may hear an individual transmitting inappropriate information over an unencrypted radio network, or simply one that is not authorized for the type of information being given. If immediately calling attention to the violation would not create an even greater security risk, the monitor will call out one of the BEADWINDOW codes^[9] used by Australia, Canada, New Zealand, the United Kingdom, the United States, and other nations working under their procedures. Standard BEADWINDOW codes (e. g. , "BEADWINDOW 2") include:

1. Position: (e. g. , disclosing, in an insecure or inappropriate way, "Friendly or enemy position, movement or intended movement, position, course, speed, altitude or destination or any air, sea or ground element, unit or force.
2. Capabilities: "Friendly or enemy capabilities or limitations. Force compositions or significant casualties to special equipment, weapons systems, sensors, units or personnel. Percentages of fuel or ammunition remaining. "
3. Operations: "Friendly or enemy operation – intentions progress, or results. Operational or logistic intentions; mission participants flying programmes; mission situation reports; results of friendly or enemy operations; assault objectives. "
4. Electronic warfare (EW): "Friendly or enemy electronic warfare (EW) or emanations control (EMCON) intentions, progress, or results. Intention to employ electronic countermeasures (ECM); results of friendly or enemy ECM; ECM objectives; results of friendly or enemy electronic counter-countermeasures (ECCM); results of electronic support measures/tactical SIGINT (ESM); present or intended EMCON policy; equipment affected by EMCON policy. "
5. Friendly or enemy key personnel: "Movement or identity of friendly or enemy officers, visitors, commanders; movement of key maintenance personnel indicating equipment limitations. "
6. Communications security (COMSEC): "Friendly or enemy COMSEC breaches. Linkage of codes or codewords with plain language; compromise of changing frequencies or linkage with line number/circuit designators; linkage of changing call signs with previous call signs or units; compromise of encrypted/classified call signs; incorrect authentication procedure. "
7. Wrong circuit: "Inappropriate transmission. Information requested, transmitted or about to be transmitted which should not be passed on the subject circuit because it either requires greater security protection or it is not appropriate to the purpose for which the circuit is provided. "
8. Other codes as appropriate for the situation may be defined by the commander.

In WWII, for example, the Japanese Navy made possible the interception and death of the Combined Fleet commander, Admiral Isoroku Yamamoto, by BEADWINDOW 5 and 7 violations. Fleet Admiral ( 4 April 1884 – 18 April 1943) was the Commander-in-chief of the Combined Fleet during World War II a They identified a key person's movement over a low-security cryptosystem.

ELINT

ELINT stands for ELectronic Signals INTelligence, and refers to intelligence-gathering by use of electronic sensors. Intelligence Gathering Disciplines HUMINT Human Intelligence - gathered from a person on the ground Its primary focus lies on non-communications signals intelligence. The Joint Chiefs of Staff define it as "Technical and geolocation intelligence derived from foreign noncommunications electromagnetic radiations emanating from other than nuclear detonations or radioactive sources. "^[2]

Signal identification is performed by analyzing the collected parameters of a specific signal, and either matching it to known criteria, or recording it as a possible new emitter. ELINT data is usually highly classified information, and is protected as such.

The data gathered is typically pertinent to the electronics of an opponent's defense network, especially the electronic parts such as radars, surface-to-air missile systems, aircraft, etc. Radar is a system that uses electromagnetic waves to identify the range altitude direction or speed of both moving and fixed objects such as Aircraft, ships A surface to air missile ( SAM) or ground-to-air missile ( GTAM) is a Missile designed to be launched from the ground to destroy Aircraft ELINT can be used to detect ships and aircraft by their radar and other electromagnetic radiation; commanders have to make choices between not using radar (EMCON), intermittently using it, or using it and expecting to avoid defenses. EMCON ( Em issions Con trol is a Military condition in which electromagnetic emissions do not exceed a set limit ELINT can be collected from ground stations near the opponent's territory, ships off their coast, aircraft near or in their airspace, or by satellite.

Complementary relationship to COMINT

Combining other sources of information and ELINT allows traffic analysis to be performed on electronic emissions which contain human encoded messages. Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in Communication. The method of analysis differs from SIGINT in that any human encoded message which is in the electronic transmission is not analyzed during ELINT. What is of interest is the type of electronic transmission and its location. For example during the Battle of the Atlantic in World War II, Ultra COMINTwas not always available because Bletchley Park was not always able to read the U-Boat Enigma traffic. The Battle of the Atlantic was the longest continuous Military campaign of World War II, (though some say it was a series of naval Military campaigns World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including ULTra ("Urban Light Transport" is a Personal rapid transit system from Advanced Transport Systems Ltd a company based in Cardiff, Wales. Bletchley Park, also known as Station X, is an estate located in the town of Bletchley, in Buckinghamshire, and (since 1967 part of Milton Keynes The Enigma machine is any one of a family of related electro-mechanical Rotor machines used to generate Ciphers for the Encryption and decryption of But "Huff-Duff" (High Frequency Direction Finder) was still able to find where the U-Boats were by analysis of radio transmissions and the positions through triangulation from the direction located by two or more Huff-Duff systems. High frequency direction finder is usually known by its Acronym HF/DF, pronounced Huff-Duff. U-boat is the anglicized version of the German word, itself an abbreviation of Unterseeboot ( undersea boat) and refers The Admiralty was able to use this information to plot courses which took convoys away from high concentrations of U-Boats. The Admiralty was formerly the authority in the United Kingdom responsible for the command of the Royal Navy.

Yet other ELINT disciplines include intercepting and analyzing enemy weapons control signals, or the Identification, friend or foe responses from transponders in aircraft used to distinguish enemy craft from friendly ones. Secondary Surveillance Radar ( SSR) is a Radar system used in Air traffic control (ATC which not only detects and measures the position of aircraft

Role in Air Warfare

A very common area of ELINT is intercepting radars and learning their locations and operating procedures. Attacking forces may be able to avoid the coverage of certain radars, or, knowing their characteristics, electronic warfare units may jam radars or send them deceptive signals. Electronic warfare ( EW) is the use of the Electromagnetic spectrum to effectively deny the use of this medium by an adversary while optimizing its use by friendly Confusing a radar electronically is called a "soft kill", but military units will also send specialized missiles at radars, or bomb them, to get a "hard kill".

Knowing where each surface-to-air missile and anti-aircraft artillery system is and its type means that air raids can be plotted to avoid the most heavily defended areas and to fly on a flight profile which will give the aircraft the best chance of evading ground fire and fighter patrols. Anti-aircraft warfare, or air defense, is any method of engaging hostile military Aircraft in defence of ground objectives, ground or naval forces It also allows for the jamming or spoofing of the enemy's defence network (see electronic warfare). In the context of Network security, a spoofing attack is a situation in which one person or program successfully masquerades as another by falsifying data and thereby gaining Electronic warfare ( EW) is the use of the Electromagnetic spectrum to effectively deny the use of this medium by an adversary while optimizing its use by friendly Good electronic intelligence can be very important to stealth operations; stealth aircraft are not totally undetectable and need to know which areas to avoid. Stealth aircraft are Aircraft that use Stealth technology to make it harder to be detected by radar and other means than conventional aircraft by employing a Similarly, conventional aircraft need to know where fixed or semi-mobile air defence systems are so that they can shut them down or fly around them. Anti-aircraft warfare, or air defense, is any method of engaging hostile military Aircraft in defence of ground objectives, ground or naval forces

ELINT and ESM

Electronic Support Measures (ESM) are really ELINT techniques, but the term is used in the specific context of tactical warfare. ESM give the information needed for Electronic Attack (EA) such as jamming. EA is also called Electronic Counter-Measures. ESM provides information needed for Electronic Counter-Counter Measures (ECCM), such as understanding a spoofing or jamming mode so one can change one's radar characteristics to avoid them.

ELINT for Meaconing

Meaconing^[10] is the combined intelligence and electronic warfare of learning the characteristics of enemy navigation aids, such as radio beacons, and retransmitting them with incorrect information. There are tales, perhaps apocryphal, that the meaconing was so confusing that an enemy aircraft landed, quite smoothly, at an airport of the other side.

FISINT

Main article: FISINT

FISINT (Foreign instrumentation signals intelligence) is a sub-category of ELINT, monitoring primarily non-human communication. FISINT stands for F oreign I nstrumentation S ignals INT elligence Foreign instrumentation signals include (but not limited to) telemetry (TELINT), tracking systems, and video data links. Telemetry (synonymous with Telematics) is a Technology that allows the remote measurement and reporting of Information of interest to the system designer TELINT is an important part of national means of technical verification for arms control. National technical means of verification is a phrase that first appeared but was not detailed in the Strategic Arms Limitation Treaty (SALT between the US and USSR

Counter-ELINT

Still at the research level are techniques that can only be described as counter-ELINT, which would be part of a SEAD campaign. Measurement and Signature Intelligence, or MASINT, refers to intelligence gathering activities that bring together disparate elements that do not fit within the SEAD (pronounced see-add or seed or Suppression of Enemy Air Defences, also known as " Wild Weasels quot and "Iron Hand" operations in the USA are It may be informative to compare and contrast counter-ELINT with ECCM. Electronic counter-countermeasures (ECCM describes a variety of practices which attempt to reduce or eliminate the effect of Electronic countermeasures (ECM on electronic

SIGINT versus MASINT

Main article: MASINT

SIGINT and Measurement and Signature Intelligence (MASINT) are closely, and sometimes confusingly, related. Measurement and Signature Intelligence, or MASINT, refers to intelligence gathering activities that bring together disparate elements that do not fit within the Measurement and Signature Intelligence, or MASINT, refers to intelligence gathering activities that bring together disparate elements that do not fit within the ^[11] The SIGINT disciplines of communications and electronic intelligence focus on the information in those signals themselves, as with COMINT detecting the speech in a voice communication or ELINT measuring the frequency, pulse repetition rate, and other characteristics of a radar. A Radar System uses a Radio Frequency electromagnetic signal reflected from a target to determine information about that target

MASINT also works with collected signals, but is more of an analysis discipline. There are, however, unique MASINT sensors, typically working in different regions or domains of the electromagnetic spectrum, such as infrared or magnetic fields. While NSA and other agencies have MASINT groups, the Central MASINT Office is in the Defense Intelligence Agency (DIA).

Where COMINT and ELINT focus on the intentionally transmitted part of the signal, MASINT focuses on unintentionally transmitted information. For example, a given radar antenna will have sidelobes emanating from other than the direction in which the main antenna is aimed. In antenna engineering side lobes are the lobes of the far field Radiation pattern that are not the main beam, where the terms "beam" The RADINT (radar intelligence) discipline involves learning to recognize a radar both by its primary signal, captured by ELINT, and its sidelobes, perhaps captured by the main ELINT sensor, or, more likely, a sensor aimed at the sides of the radio antenna.

MASINT associated with COMINT might involve the detection of common background sounds expected with human voice communications. For example, if a given radio signal comes from a radio used in a tank, if the interceptor does not hear engine noise or higher voice frequency than the voice modulation usually uses, even thought the voice conversation is meaningful, MASINT might suggest it is a deception, not coming from a real tank. In Telecommunications, modulation is the process of varying a periodic Waveform, i

See HF/DF for a discussion of SIGINT-captured information with a MASINT flavor, such as determining the frequency to which a receiver is tuned, from detecting the frequency of the beat frequency oscillator of the superheterodyne receiver. High frequency direction finder is usually known by its Acronym HF/DF, pronounced Huff-Duff. A beat frequency oscillator or BFO in Radio telegraphy, is a dedicated Oscillator used to create an audio frequency signal from Carrier wave In Electronics, the superheterodyne receiver (also known by its full name the supersonic heterodyne receiver, or by the abbreviated form superhet) is a

Defensive SIGINT

There are a number of ways that a person or organization can defend against SIGINT. There is a delicate balance between the level of protection and the actual threat, as expressed in the clichés about "tinfoil hats".

One must begin by defining the threat. It is considerably more difficult to defend against detection that one is signaling, as opposed to defending against an opponent discovering the content of the transmitted message. Appropriate encryption can protect against content interception, but protecting against signal detection, especially with a capable opponent, requires measures to make the signal hard to detect – which can also make it difficult for the intended recipient to receive the signal. Any defensive program needs to consider the nature of the threat and the capabilities of the opponent.

Strong and well-managed encryption

While encryption is discussed at length in other articles, it should not be forgotten that if one wants to protect messages and files, encryption is central to the defense. As important as the encryption process itself may be, it is vulnerable if the cryptographic keys are not strong and protected, and, on computers, that the cleartext is deleted when not needed. In Cryptography, a key is a piece of information (a Parameter) that determines the functional output of a cryptographic algorithm In Data communications, cleartext is the form of a message or data which is in a form that is immediately comprehensible to a human being without additional processing Seemingly obvious, but too often neglected, is making a practice of having as little cleartext hard copy as possible.

Appropriate transmission security

When using radio transmitters, use directional antennas that have as little "spillover" into sidelobes as possible. A directional antenna or beam antenna is an antenna which radiates greater power in one or more directions allowing for increased performance on transmit and receive In antenna engineering side lobes are the lobes of the far field Radiation pattern that are not the main beam, where the terms "beam" If it is most important to hide the location of a transmitter, the minimum is to cable the antennas as far as possible away from the transmitter proper. In many circumstances, aiming the antenna upward to a satellite will help hide its location.

The amount of total transmission power needs to be minimized, and the power preferably should be split into multiple and changing frequencies using spread spectrum techniques. Spread-spectrum techniques are methods by which Energy generated in a particular bandwidth is deliberately spread in the Frequency domain, resulting If possible, avoid transmitting when hostile SIGINT satellites or monitoring aircraft are overhead.

If in an urban area, avoid using regular commercial power to transmit. There are ways in which the signal can "leak" into power and ground lines. The adversary may turn off power to an area, which will tell him there is a line-operated transmitter if the transmission stops, and that there is a battery-powered transmitter if it continues.

Use highly variable transmission schedules and vary frequencies if technically possible. Also see low probability of intercept.

Appropriate receiving security

If Operation RAFTER-style intercept is a threat, protect against this form of unintentional radiation MASINT by using optoisolators or other shielded techniques (e. RAFTER was a codename for the MI5 radio receiver detection technique mostly used against clandestine Soviet agents and monitoring of domestic radio transmissions Radiofrequency MASINT is one of the six major disciplines generally accepted to make up the field of Measurement and Signature Intelligence (MASINT with due regard that the g, waveguides) to bring in the radio frequency received signal, and shield the local oscillator and intermediate frequency stages in the superheterodyne receiver. Radio frequency ( RF) is a Frequency or rate of Oscillation within the range of about 3 Hz to 300 GHz A local oscillator is an electronic device used to generate a signal normally for the purpose of converting a signal of interest to a different frequency using a mixer In communications and Electronic engineering, an intermediate frequency ( IF) is a Frequency to which a carrier frequency is shifted as an In Electronics, the superheterodyne receiver (also known by its full name the supersonic heterodyne receiver, or by the abbreviated form superhet) is a This technique should be far less effective against the new generation of software-defined radio. A Software-Defined Radio (SDR system is a Radio communication system where components that have typically been implemented in hardware (i

Unintentional radiation on power or ground circuits is a threat here as well; use appropriate TEMPEST or other techniques.

Protection against compromising emanations

There are risks that electronic, acoustic, or other information could "leak" from a computer system or other electronic communications devices.

The Risk

Understanding details of the risks requires a substantial knowledge of electronics, but a simple example might serve. Many people have put a radio receiver near a computer, to listen to music as they work, and discovered that the radio suffered clicks, squeals, and other interference. These interfering signals are radiating from various parts of the computer, especially its display but often also from the power and grounding system. TEMPEST is the name for one family of protective measures against an opponent intercepting these emanations and extracting sensitive information from them.

While not strictly within the scope of protecting against "leakage", a place where sensitive information is processed or discussed needs protection against hidden microphones, wiretaps, and other "bugging". Sometimes, an electronic sweep to verify TEMPEST compliance reveals the presence of hidden transmitters. Again, there is probably more suspicion than reality in most cases. A member of a crime organization, in the middle of a nasty divorce, or a foreign intelligence agent might have reason to worry, but, even with the serious questions about warrantless surveillance in the US and other countries, there is little reason for someone to go to the risk and expense of illegal surveillance on an ordinary citizen. TEMPEST is usually associated with direct electromagnetic radiation from the device, either free-space or through power and ground lines. TEMPEST generically talks about acoustic isolation, but that is fairly easily solved through physical security and noise damping, as well as searches for microphones.

There are several threats that have not been officially defined in the unclassified literature. Nevertheless, there are some informed guesses:^[12]

• NONSTOP is a threat that involves some type of coupling of compromising RF energy from a classified system, which "leaks" into an independent RF-transmitting or -recording device such as cell phones, PDAs, pager, alarm systems. Commercial AM/FM radios are not considered a risk.
• HIJACK is a similar threat of coupling, but to some type of digital computer or related equipment.
• TEAPOT is a very different vulnerability, which appears to apply to incidental audio modulation of the backscatter from an RF, typically microwave, directed into the secure area. A passive resonant cavity bug of this type was discovered in a Great Seal of the United States presented by the USSR, but containing a resonant cavity with a wall that moved with sound in the room, thus imposing frequency modulation onto the backscattered signal. A covert listening device, more commonly known as a bug, is usually a combination of a Miniature Radio transmitter with a Microphone.

Mitigation and Countermeasures

The word TEMPEST itself, and its meaning, are unclassified. Some of the techniques for measuring the compliance of a piece of equipment, or whether it is actually emitting compromising emanations, are classified. A good deal of the information has come into public view either through Freedom of Information Act queries,^[13] books talking about interception techniques, inferences drawn from partially released documents, and straightforward thinking by electronic engineers. Some documents released fully or partially under FOIA:

1. Red/Black Installation Guidance^[14]
2. Specification for Shielded Enclosures^[15]
3. Specification for Shielded Enclosures (partially redacted)^[16]

A number of individuals have made a hobby of ferreting out TEMPEST and related information,^[17] and firms in the broader-than-TEMPEST business of Technical Surveillance Countermeasures TSCM also reveal concepts. TSCM ( Technical Surveillance Counter-Measures) is the original Unites States Military Abbreviation denoting the process of bug -sweeping ^[18]

Protection against side channel attacks and covert channels

A side channel attack is an unintentional vulnerability of an encryption device, not related to the encryption algorithm. In Cryptography, a side channel attack is any attack based on information gained from the physical Implementation of a Cryptosystem, rather than brute ^[19] Potential vulnerabilities include different processing and thus transmission speeds for blocks of plaintext with certain statistical characteristics, changes in power consumption, or compromising emanations.

Covert channels are deliberate means to elude communications security. In Information theory, a covert channel is a parasitic Communications channel that draws bandwidth from another channel in order to transmit information ^[20] They send out an unauthorized signal by stealing bandwidth from a legitimate, often encrypted channel. One low-bandwidth method would be to send information by varying the inter-block transmission times. A steganographic covert channel might use the low-order bit of pixels in a graphic image, perhaps not even consecutive pixels, in a manner that would not be obvious to a person looking at the graphic. Steganography is the art and science of writing hidden messages in such a way that no one apart from the sender and intended recipient even realizes there is a hidden message

References

Further reading

• Bamford, James, Body of Secrets: How America's NSA and Britain's GCHQ eavesdrop on the world (Century, London, 2001)
• West, Nigel, The SIGINT Secrets: The Signals Intelligence War, 1900 to Today (William Morrow, New York, 1988)
• J. James Bamford (born September 24, 1946) is an American bestselling author and journalist who writes about United States intelligence agencies Rupert William Simon Allason (born 8 November, 1951) is a military historian and former Conservative Party politician in the United Kingdom A. Biyd, D. B. Harris, D. D. King & H. W. Welch, Jr. (Editors). Electronic Countermeasures. Los Altos, CA: Peninsula Publishing (1961). ISBN 0-932146-00-7.  

See also

• SIGINT by Alliances, Nations and Industries
• SIGINT Operational Platforms by Nation
• SIGINT in Modern History
• List of intelligence gathering disciplines
• Canadian Forces Intelligence Branch
• National Security Agency
• HUMINT: Human intelligence
• Communications security (COMSEC)
• ELINT: Electronic intelligence
• MASINT: Measurement and Signature Intelligence
• IMINT: Imagery intelligence
• GEOINT: Geospatial Intelligence
• Narus: SIGINT hardware manufacturer referred to in Hepting vs. AT&T
• OSINT: Open Source Intelligence
• U.S. Marine Corps Radio Reconnaissance
• RAF Intelligence: Royal Air Force Intelligence Branch
• Traffic analysis
• Historical Electronics Museum
• Central Intelligence Agency Directorate of Science & Technology

External links

• http://www.nsa.gov/sigint/ - SIGINT Overview
• http://www.nsa.gov/sigint/sigin00003.cfm - SIGINT FAQ
• http://www.fas.org/spp/military/program/sigint/overview.htm
• http://groups-beta.google.com/group/sigint - SIGINT Google Group
• http://www.economist.com/daily/columns/europeview/displaystory.cfm?story_id=10950261&fsrc=nwl - Seen from on high
• David Alan Jordan, Decrypting the Fourth Amendment: Warrantless NSA Surveillance and the Enhanced Expectation of Privacy Provided by Encrypted Voice over Internet Protocol - Boston College Law Review, Vol. Intelligence Gathering Disciplines HUMINT Human Intelligence - gathered from a person on the ground The Intelligence (Int Branch is a Personnel branch of the Canadian Forces (CF The National Security Agency/ Central Security Service ( NSA/CSS) is a cryptologic intelligence agency of the United States government HUMINT, a syllabic abbreviation of the words HUMan INTelligence refers to intelligence gathering by means of interpersonal contact as opposed to the more technical Communications security ( COMSEC) Measures and controls taken to deny unauthorized persons Information derived from Telecommunications and ensure Measurement and Signature Intelligence, or MASINT, refers to intelligence gathering activities that bring together disparate elements that do not fit within the IMINT, short for IM agery INT elligence is an intelligence gathering discipline which collects information via satellite and Aerial photography GEOINT stands for GEOspatial INTelligence, which is an intelligence discipline comprising the exploitation and analysis of Satellite information to describe Narus is a private company founded in 1997 by Ori Cohen, who had been in charge of technology development for VDONet, an early Media streaming pioneer Hepting v AT&T is a United States Class action lawsuit filed in January 2006 by the Electronic Frontier Foundation (EFF against This article is a subset article in a series under Intelligence collection management. The Radio Reconnaissance Platoon is a specially-trained element of a United States Marine Corps Radio Battalion. The Royal Air Force Operations Support (Intelligence Branch is an organisation within the Royal Air Force that maintains intelligence staff and equipment Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in Communication. The Historical Electronics Museum loacated in Linthicum Maryland, displays the history of the United States defense electronics See also Central Intelligence Agency The Directorate of Science and Technology is the branch of the United States Central Intelligence Agency (CIA charged 47, 2006
• http://www.signami.com/SRBWCalc.htm - Handy calculator for determining bandwidths and optimum sampling rates for subsampled IF digitizing.