Editing Traffic analysis (section)

==Examples==
For example, if an emitter is known as the radio transmitter of a certain unit, and by using [[direction finding]] (DF) tools, the position of the emitter is locatable, the change of locations from one point to another can be deduced, without listening to any orders or reports. If one unit reports back to a command on a certain pattern, and another unit reports on the same pattern to the same command, the two units are probably related. That conclusion is based on the [[metadata]] of the two units' transmissions, not on the content of their transmissions.

Using all or as much of the metadata available is commonly used to build up an [[SIGINT#Electronic order of battle|Electronic Order of Battle]] (EOB) by mapping different entities in the battlefield and their connections. Of course, the EOB could be built by tapping all the conversations and trying to understand, which unit is where, but using the metadata with an automatic analysis tool enables a much faster and accurate EOB build-up, which, alongside tapping, builds a much better and complete picture.

===World War I===
* British analysts during [[World War I]] noticed that the [[call sign]] of German Vice Admiral [[Reinhard Scheer]], commanding the hostile fleet, had been transferred to a land station. [[Admiral of the Fleet (Royal Navy)|Admiral of the Fleet]] [[David Beatty, 1st Earl Beatty|Beatty]], ignorant of Scheer's practice of changing call signs upon leaving harbour, dismissed its importance and disregarded [[Room 40]] analysts' attempts to make the point. The German fleet sortied, and the British were late in meeting them at the [[Battle of Jutland]].<ref name="Kahn">{{cite book
 | title = The Codebreakers: The Story of Secret Writing
 | url = https://archive.org/details/codebreakerssto00kahn
 | url-access = registration
 | author = Kahn, David
 | year = 1974
 | id = Kahn-1974
 | publisher = Macmillan 
 | isbn = 0-02-560460-0
 }}</ref> If traffic analysis had been taken more seriously, the British might have done better than a "draw".{{original research inline|date=August 2009}}
* French military intelligence, shaped by [[Auguste Kerckhoffs]]'s legacy, had erected a network of intercept stations at the Western Front in pre-war times. When the Germans crossed the frontier, the French worked out crude means for direction-finding based on intercepted signal intensity. The recording of call signs and of traffic volumes further enabled the French to identify German combat groups and to distinguish fast-moving cavalry from slower infantry.<ref name="Kahn"/>

===World War II===
* In the early part of [[World War II]], the [[aircraft carrier]] {{HMS|Glorious}} was evacuating pilots and planes from [[Norway]]. Traffic analysis produced indications {{ship|German battleship|Scharnhorst||2}} and {{ship|German battleship|Gneisenau||2}} were moving into the [[North Sea]], but the Admiralty dismissed the report as unproven. The captain of ''Glorious'' did not keep sufficient lookout and was subsequently surprised and sunk. [[Harry Hinsley]], the young [[Bletchley Park]] liaison to the Admiralty, later said that his reports from the traffic analysts were taken much more seriously thereafter.<ref>{{cite web
 |url         = http://www.warship.org/no11994.htm
 |title       = The Loss of HMS Glorious: An Analysis of the Action
 |author      = Howland, Vernon W.
 |date        = 2007-10-01
 |access-date  = 2007-11-26
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20010522092000/http://www.warship.org/no11994.htm
 |archive-date = 2001-05-22
}}</ref>
* During the planning and rehearsal for the [[attack on Pearl Harbor]], very little traffic was passed by radio, subject to interception. The ships, units, and commands involved were all in Japan and in touch by phone, courier, signal lamp, or even flag. None of that traffic was intercepted, and could not be analyzed.<ref name="Kahn"/>
* The espionage effort against Pearl Harbor before December did not send an unusual number of messages; Japanese vessels regularly called in Hawaii and messages were carried aboard by consular personnel. At least one such vessel carried some Japanese Navy Intelligence officers. Such messages could not be analyzed. It has been suggested,<ref>{{cite book
 | author = Costello, John
 | title = Days of Infamy: Macarthur, Roosevelt, Churchill-The Shocking Truth Revealed : How Their Secret Deals and Strategic Blunders Caused Disasters at Pear Harbor and the Philippines
 | publisher = Pocket
 | year = 1995
 | isbn = 0-671-76986-3
 | url-access = registration
 | url = https://archive.org/details/daysofinfamymaca0000cost
 }}</ref> however, the volume of diplomatic traffic to and from certain [[consular office|consular stations]] might have indicated places of interest to Japan, which might thus have suggested locations to concentrate traffic analysis and decryption efforts.{{Citation needed|date=November 2007}}
* [[Nagumo Chuichi|Admiral Nagumo]]'s Pearl Harbor Attack Force sailed under radio silence, with its radios physically locked down. It is unclear if that deceived the US since Pacific Fleet intelligence had been unable to locate the Japanese carriers in the days immediately preceding the [[attack on Pearl Harbor]].<ref name="Kahn"/>
* The [[Imperial Japanese Navy|Japanese Navy]] played radio games to inhibit traffic analysis (see Examples, below) with the attack force after it sailed in late November. Radio operators normally assigned to carriers, with a characteristic Morse Code "[[Telegraph key#"Fist"|fist]]", transmitted from inland Japanese waters, suggesting the carriers were still near Japan.<ref name="Kahn"/><ref>{{cite book
 | title =  "And I Was There": Pearl Harbor And Midway -- Breaking the Secrets.
 | url =  https://archive.org/details/andiwastherepear00layt
 | url-access =  registration
 | author = Layton, Edwin T.
 |author2=Roger Pineau, John Costello
 | publisher = William Morrow & Co
 | year = 1985
 | isbn  =0-688-04883-8
}}</ref>
* [[Operation Quicksilver (WWII)|Operation Quicksilver]], part of the British deception plan for the [[Invasion of Normandy]] during World War II fed German intelligence a combination of true and false information about troop deployments in Britain, which caused the Germans to deduce an order of battle that suggested an invasion at the [[Pas-de-Calais]], instead of Normandy. The fictitious divisions that were created for the deception were supplied with real radio units, which maintained a flow of messages that was consistent with the deception.<ref>{{cite book |last=Masterman |first=John C |author-link=John Cecil Masterman |title=The Double-Cross System in the War of 1939 to 1945 |publisher=Australian National University Press |isbn=978-0-7081-0459-0 |year=1972 |orig-year=1945|page=233 }}</ref>