Clandestine HUMINT operational techniques The Clandestine HUMINT page deals with the functions of that discipline , including espionage and active counterintelligence . This page deals with Clandestine HUMINT operational techniques , also called " tradecraft " . It applies to clandestine operations for espionage , and for a clandestine phase prior to direct action ( DA ) or unconventional warfare ( UW ) . Clandestine HUMINT sources may also act as local guides for special reconnaissance ( SR ) . Many of the techniques here are important in counterintelligence . Defensive counterintelligence personnel need to know them to recognize espionage , sabotage , etc . in process . Offensive counterintelligence specialists may actually use them against foreign intelligence services ( FIS ) . While DA and UW can be conducted by national military or paramilitary organizations , al - Qaeda and similar non - state militant groups appear to use considerably different clandestine cell system structure , for command , control , and operations , than do national forces . Cell systems are evolving to more decentralized models , sometimes because they are enabled by new forms of electronic communications . This page deals primarily with one ' s own assets . See double agent for additional information adversary sources that a country has turned to its own side . Staff and Skills in a Clandestine HUMINT Operations Station . This description is based around the foreign intelligence service , of country B , operating in and against country A . It may also include operations against non - state organizations operating in country B , with or without country B support . It may also involve offensive counterintelligence against country D assets operating in country B . The basic structure here can be pertinent to a domestic service operating against a non - national group within its borders . Depending on the legal structure of the country , there may be significant , or very few , restrictions on domestic HUMINT . The most basic question will be whether criminal prosecution , or stopping operations , is the goal . Typically , criminal prosecution will be the primary goal against drug and slavery groups , with breaking up their operations the secondary goal . These priorities , however , are apt to reverse in dealing with terrorist groups . If there are separate organizations with diplomatic and nonofficial cover , there may be two chiefs . Sufficiently large stations may have several independent , compartmented groups . Station under Diplomatic Cover . Nations vary as to how well hidden they choose to have all , part , or none of their intelligence personnel under the guise of diplomatic immunity . Frequently , at least one individual is known to the host country , so there can be a deniable channel of communications . If the nations are allies , many of the intelligence personnel may be known and actively cooperating . Certain diplomatic titles were often assumed to be cover jobs . With the United Kingdom , " passport control officer " was , much of the time , an intelligence position . Today , it may be confusing that some passport control officers actually control passports . With other countries , " cultural attaché " was often a cover job , although , again , it might be legitimate . An intelligence officer covered as a cultural attaché might still do some cultural things . Stations under Official but Nondiplomatic Cover . An intermediate approach has the officers clearly working for their country , but without diplomatic immunity and with a cover role that does not immediately suggest intelligence affiliation . For example , the Soviet GRU covered some intelligence officers under the TASS news agency , or as part of a trade or technical mission , or even as diplomats . The last might seem surprising , but this was under a GRU assumptions that military attaches would always be assumed to be intelligence officers , but that members of the civilian part of an embassy might actually be diplomats rather than intelligence officers . It was easier , of course , for the socialist USSR to assign people to state agencies . Western sensitivities tend to be much greater about using , for example , journalistic cover . The US has been emphatic in prohibiting any relationship between intelligence and the Peace Corps . US military intelligence doctrine forbids a HUMINT specialist to pose as : An example of civilian cover for an American officer involved a German refugee , with the pseudonym " Stephan Haller " , who had widely ranging interests and special skills in mathematics and physics , as well as native language skill . His overt role , in 1949 , was directing a program that paid subsidies to German scientists , part of a larger program of denying German talent to the Soviets . Initially , he was based in Pforzheim , ( West ) Germany . After two years in Pforzheim , he had a well - established cover , and had been collecting political and scientific intelligence to the scientists , and also Germans that he knew in political circles before emigrating . In 1951 , he moved to Berlin , directing overall " operations against scientific targets in the East Zone of Germany " , while still managing the subsidy program . His new work included encouraging defection of key craftsmen working for the Soviets . He was considered a master craftsman , He did not grow careless or conceited with success . Here remained a meticulous craftsman . Before he debriefed a source , he mastered the subject to be discussed . His agents were made comfortable not only by his cigars and beer but also by the easy flow of communication . And he did not end until he had every last scrap of useful information . He never failed , moreover , to remain alert for operational leads - - potential agents , counterintelligence indicators , propaganda possibilities . When Haller was finished , there were no more questions to be asked . And though he groaned over the chore of putting it on paper , his reporting became thorough - and more than thorough , illuminating - for he rarely failed to make interpretive comments . Stations under Nonofficial Cover . According to Victor Suvorov , the Soviet reaction to losing networks operated from diplomatic missions , after the countries in which those embassies were overrun in the Second World War , Soviet practice was to emphasize " illegal " ( i . e . , what the US calls nonofficial cover ) stations ( i . e . , residencies ) for HUMINT networks . The illegal residencies were preferred to be in safe locations , perhaps of allies such as the United States , Great Britain and Canada . Soviet operations were tightly compartmented , with strict need - to - know an absolute rule . " Undercover residencies support illegals , but only on instructions from the Centre without having any idea for whom they are working . All operations in support of illegals are worked out in such a way that the officers of the GRU undercover residency do not have one crumb of information which is not necessary . Operations are planned in such a way that there is no possibility of the illegals becoming dependent on the actions of the undercover residency . " A lesson learned from the loss of espionage networks was to keep them small , subdividing them , with independent reporting to Center , when more agents were recruited . Moving new agents into illegal residencies . Suvorov explained that new agents were separated from official Soviet institutions only after the agent has compromised himself , by giving Soviet Intelligence a significant quantity of secret material , that is , made it impossible for himself to go to the police . The separated agent comes in three guises : the separated acting agent , the agent group and the agent residency . Separated acting agent . The most resources are devoted to the agents that provide the most important material . Once the central headquarters assesses the agent ' s information as highly valuable , the doctrine is to stop , temporarily , obtaining new material , and improving his security and education in espionage tradecraft . The training is preferably done in a third country , from which he might or might not be moved to the Soviet Union . His absence typically would be covered by taking a vacation or holiday . Thence he will go back to his own country , but as an independently acting agent . He will be run exclusively by the Centre , in concrete terms the head of a section , even , in special cases , the head of a directorate and in extreme cases the deputy head of the GRU or the head himself . The running of such an agent is thus carried out exactly as the running of illegals is . Agent group . The next category of agent , less valuable than a separated acting agent but still of importance , was the agent group , which migrated from diplomatic or civilian contact , to the in - country illegal " rezidentura " ( resident and infrastructure ) , to direct communications with the Center . The leader of such a group is called , in Soviet terminology , a " gropovod " , and is conceptually the only member of the group that communicates with Moscow . In reality , clandestine communications personnel may be aware of the direct contact , but newer electronics allow the leader to manage his or her only communications . Suvorov makes the important point that " A group automatically organises itself . The GRU obviously considers family groups containing the head of the family and his wife and children to be more secure and stable . The members of such a group may work in completely different fields of espionage . " The pattern of having groups that are self - organizing and have preexisting ties , making them virtually impossible to infiltrate , has survived the GRU and is common in terrorist networks . Other agents recruited by residencies are gradually organised into agent groups of three to five men each . Usually , agents working in one particular field of espionage are put together in one group . Sometimes a group consists of agents who for various reasons are known to each other . Let us suppose that one agent recruits two others . . . . Thus to a certain extent the members of agent groups are completely isolated from Soviet diplomatic representation . The agent group is in contact with the undercover residency for a period of time , then gradually the system of contact with the residency comes to an end and orders begin to be received directly from Moscow . By various channels the group sends it material directly to Moscow . Finally the contact with Moscow becomes permanent and stable and the agent group is entirely separated from the residency . With gradual changes in personnel at the residency , like the resident himself , the cipher officers and the operational officers with whom there was once direct contact , nobody outside the Centre will know of the existence of this particular group . Should it happen that operating conditions become difficult , or that the embassy is blockaded or closed down , the group will be able to continue its activities in the same way as before . Agent residency . When the GRU attaches one or more illegals ( i . e . , Soviet officer under an assumed identity ) , the residency changes from " an agent residency into an illegal residency . This process of increasing the numbers and the gradual self - generation of independent organisations continues endlessly . " Suvorov uses a medical metaphor of quarantine designed to contain infection to describe separating agents for improved security . The GRU kept certain officers immediately ready to go into illegal status , should the host nation intensify security . These officers are in possession of previously prepared documents and equipment , and gold , diamonds and other valuables which will be of use to them in their illegal activities will have been hidden in secret hiding - places beforehand . In case of war actually breaking out , these officers will unobtrusively disappear from their embassies . The Soviet government will register a protest and will for a short time refuse to exchange its diplomats for the diplomats of the aggressive country . Then it will capitulate , the exchange will take place and the newly fledged illegals will remain behind in safe houses and flats . Afterwards they will gradually , by using the system of secret rendezvous , begin to establish the system of contacts with agents and agent groups which have recently been subordinated to the undercover residency . Now they all form a new illegal residency . The new illegals never mix and never enter into contact with the old ones who have been working in the country for a long time . This plainly makes life more secure for both parties . Again , Suvorov emphasizes that the process of forming new illegal residencies was the Soviet doctrine for imposing compartmentation . Western countries , especially those in danger of invasion , have a related approach , the stay - behind network . The US military definition , used by most NATO countries , is Agent or agent organization established in a given country to be activated in the event of hostile overrun or other circumstances under which normal access would be denied . In such an approach , both clandestine intelligence and covert operations personnel live normal lives , perhaps carrying out regular military or government functions , but have prepared documentation of assumed identities , safehouses , secure communications , etc . A representative illegal residency . Vilyam Genrikhovich Fisher , usually better known by his alias , Rudolf Abel , was a Soviet intelligence officer who came to the US under the false identity of a US citizen , Emil Robert Goldfus , who had died in infancy but was used by the USSR to create an elaborate legend for Fisher . On coming to the US , entering through Canada , Fisher / Abel took over the control of several existing Soviet HUMINT assets , and also recruited new assets . Key assets for whom he was the case officer included Lona Cohen and Morris Cohen , who were not direct intelligence collectors but couriers for a number of agents reporting on US nuclear information , including Julius Rosenberg , Ethel Rosenberg , David Greenglass , and Klaus Fuchs . His role was that of the " illegal " resident in the US , under nonofficial cover . Soviet practice often was to have two rezidents , one illegal and one a diplomat under official cover . He was betrayed to the US by an alcoholic assistant who defected to the FBI . That Fisher / Abel only had one assistant , with operational responsibilities , is not surprising . Unless a clandestine station has a strong cover identity , the larger the station , the larger the possibility it may be detected by counterintelligence organizations . Beyond the station chief , the most likely person to be associated with the station , not as a case officer , is a communicator , especially if highly specialized secure communication methods are used . Support Services . Some clandestine services may have additional capabilities for operations or support . Key operational agents of influence are apt to be run as singletons , although political considerations may require communication through cutouts . Useful idiots can be run by diplomatic case officers , since there is no particular secrecy about their existence or loyalty . Valuable volunteers , depending on the size of the volunteer group , may work either with case officers , or operations officers brought clandestinely into the area of operations . Transportation , Infiltration , Exfiltration , Logistics . Proprietaries , which can be large businesses ( e . g . , the CIA proprietary airlines such as Air America , which , in the interest of cover , often had the latest aircraft and flew commercial as well as secret cargo ) , often are not controlled from the local area , but by headquarters . Especially when the proprietary is a multinational company , and has some commercial business of its own , central control makes the most sense . In looking at internal as well as external assets , remember the fundamental rule of clandestine operations : the more secure , the less efficient . Because espionage operations need rigorous security , they are always inefficient — they take a lot of time , energy , and money . Proprietaries can be an exception , but , even though they make money , they can require additional capital to be able to expand in the same way a comparable private business would do so . Volunteer and Proprietary Support . Sayanim are Jews living outside Israel as foreign citizens that volunteer to provide assistance to the Mossad . This assistance includes facilitating medical care , money , logistics , and even overt intelligence gathering , yet sayanim are only paid for their expenses . No official number is known , but estimates put the number of sayanim in the thousands . The existence of this large body of volunteers is one reason why the Mossad operates with fewer case officers than fellow intelligence agencies . Another kind of resource could include foreign offices owned or operated by nationals of the country in question . A step farther is a proprietary , or business , not just individuals , under non - official cover . Both kinds of business can provide information from recruitment , unwitting agents , or support functions . Small and medium aviation - related businesses have been popular US proprietaries , including Air America and Southern Air Transport . Once the service has a presence in aviation , it may become aware of persons , in private business , civil service , or the military , who fly to destinations of interest . They may mention it in innocent conversation , such as at the airport ' s restaurant or bar . They also may be assumed to be going there , based by analysis of flight departure times , aircraft type , duration of trip , and their passengers or cargo . Having routine access to an airport can reveal : " Who ’ s coming and going , on and off the record ? What ’ s in the hangars and warehouses ? What are the finances ? Political connections and loyalties ? Access to planes on the ground ? Flight plans ? " It must be emphasized that a transportation - related proprietary — truck stops , boat maintenance , and other industry - specific businesses , have to operate as a real business . Occasionally , they may produce a profit , and that can be confusing for headquarters financial managers , provide a local but perhaps traceable source of funds , or both Public relations firms have long been useful proprietaries . In a given country of operations , or perhaps adjacent countries that are concerned about the actions of their neighbor , news releases placed by experienced public relations professionals can help mold relevant opinion . Care must be taken that the news release does not " blow back " on the clandestinely sponsoring country . Another viable industry for proprietaries is natural resources exploration . If , hypothetically , a mining company operated in a country where there are both resources deposits and non - national group sanctuaries , a proprietary company could get information on both , and also provide access and support services . If the proprietary began mining operations , it would naturally have access to explosives , which might be made available to sabotage groups in neighboring areas . Use of nongovernmental organizations ( NGO ) is politically sensitive and may require approval at the highest level of an agency . Sometimes , there is a broader policy need not to have the possibility of drawing suspicion onto an NGO . For example , in WWII , it was occasionally necessary to send supplies to Allied POWs , but Red Cross parcel s were never ever used for this purpose . The decision had been made that Red Cross parcels were important to the survival of the POWs and could never be jeopardized . Safehouses . " Safehouse " is a term of intelligence tradecraft whose origins may be lost in antiquity . " The Bible is also replete with instances of espionage , including Yahweh ’ s instruction to Moses to send spies into the land of Canaan . The account of the harlot Rahab sheltering Israelite spies and betraying the city of Jericho might be the first documented instance of a " safe house . " The term is not strictly limited to houses , although many intelligence services use rural houses for extended functions such as debriefing defectors . In a city , a safehouse may be an apartment or house that is not known to be associated with an intelligence service . Another usage refers to mailing addresses ( postal and electronic ) and telephone numbers , to which messages can be sent with a reasonable chance of not coming into the awareness of counter - intelligence . Useful Idiots . Useful idiot is a term attributed to Lenin , principally in Soviet use , for a person overtly supporting the interests of one country ( e . g . , the USSR ) in another ( e . g . , a member of the overt Communist Party of the second country ) . Soviet intelligence practice was to avoid such people in the actual clandestine operations , regarding them at most useful as distractions to the counterintelligence services . Agents of influence , who were witting of Communist plans and intended to influence their own country ' s actions to be consistent with Soviet goals , went to great lengths to conceal any affiliation . " Witting " is a term of intelligence art that indicates that one is not only aware of a fact or piece of information , but also aware of its connection to intelligence activities . VENONA COMINT exposes that Alger Hiss and Harry Dexter White , accused of Communist sympathies , were indeed Soviet spies . They were Communist agents , and the Soviets certainly did not treat them as useful idiots . There were communications with them , and the dialogues were clandestine . Gus Hall also had overt Communist affiliation , and it is extremely unlikely Soviet clandestine operatives would have had anything to do with him . Still , in situations such as emergency exfiltration , Party members in a Western country might be called upon as a last desperate resort . Basic Agent Recruiting . This section deals with the recruiting of human resources who do not work for a foreign intelligence service ( FIS ) . For techniques of recruiting FIS personnel , see Counterintelligence . In principle and best practice , all country B officers in country A report to an executive function in their home country . In CIA terms , this might be a head of a country desk or a regional desk . Russian practice was to refer to " Center " . Actual recruiting involves a direct approach by a case officer who has some existing access to the potential recruit , an indirect approach through an access agent or proprietary , or has reason to risk a " cold " approach . Before the direct recruitment , there may be a delicate period of development . For details , see Clandestine HUMINT asset recruiting . Basic Agent Operations . This section deals with the general structure of running espionage operations . A subsequent section deals with Specialized Clandestine Functions , and another with Support Services for both basic and specialized operations The agent may join , or even create , a new network . In the latter case , the agent may be called a " lead agent " or a " principal agent " . The latter term is also refers to access agents , who only help in recruiting . Well - managed agent relationships can run for years and even decades ; there are cases where family members , children at the time their parents were recruited , became full members of the network . Not all agents , however , operate in networks . A Western term for agents controlled as individuals is singleton . This term usually is reserved for the first or most sensitive recruitments , although specialized support personnel , such as radio operatives acting alone , are called singletons . In Soviet tradecraft , the equivalent of a singleton is a separated acting agent . Professional intelligence officers , such as Robert Hanssen , may insist on being singletons , and go even farther , as with Hanssen , refuse in - person meetings . Even as a singleton , the agent will use security measures such as secure communication s . Agents also may operate in networks , for which the classic security structure is the . The agent may join a proprietary , although that is more likely to be for access or support agents . Training . Before the agent actually starts to carry out assignment , training in tradecraft may be necessary . For security reasons , this ideally will be done outside the agent ' s own country , but such may not always be possible . Increasingly less desirable alternatives might be to conduct the training away from the operational area , as in a safe house in a resort , and then a safe house inside the operational area . Among the first things to be taught are communications tradecraft , beginning with recording the material of interest . Skills here can include the operation of cameras appropriate for espionage , methods of carrying out documents without detection , secret writing . Once the information is captured , it must be transmitted . The transmission may be impersonal , as with dead drops or car tosses . It may involve carriers . It may be electronic . If there is a need for personal meetings , the agent must know how to request them , and also to alert the network leader or case officer that the agent may be under suspicion . Teaching countersurveillance techniques to agents is a calculated risk . While it may be perfectly valid for an agent to abort a drop or other relatively innocent action , even at the cost of destroying valuable collected material , it is much more dangerous to teach the agent to elude active surveillance . The ability to elude professional counterintelligence personnel following the agent , for example , may confirm the counterintelligence organization ' s suspicion that they are dealing with a real agent . Still , the agent may need to have an emergency escape procedure if he confirms he is under surveillance , or even if he is interrogated but released . Continued Testing during Operations . Case officers should constantly test their agents for changes in motivation or possible counterintelligence compromise . While " name traces cannot be run on every person mentioned by the agent , do not be stingy with them on persons who have familial , emotional , or business ties with him " to detect any linkages to hostile counterintelligence . Until an agent is well established as reliable , meetings , which always must be done with care to avoid detection , are " the prime emphasis is put on vigilance and checking - has he been planted by the local counterintelligence , are his motives in agreeing to collaborate sincere ? The need for personal meetings with such an agent is increased , for they give the opportunity to assess him more completely . " An experienced US operations officer emphasized that field operations personnel should report status and progress often . Only with such reporting can a headquarters staff looking globally for penetrations , and aware of political implications . Reporting and headquarters advice is critical for joint operations ( i . e . , with the intelligence service of another country ) . Headquarters , aware of all joint operations with that service , can give advice from a broader viewpoint , without compromising the need for local initiative . " Operating the Agent . Even with the most sensitive agents , occasional personal meetings are important in maintaining psychological control . Nevertheless , some agents , especially trained intelligence officers like Robert Hanssen , will almost never meet , but provide material good enough to prove their bona fides . A Soviet officer commented , whatever an agent ' s role in the intelligence net , personal contact should be made with him only when it is impossible to manage without it . The number of meetings should be kept as low as possible , especially with sources of valuable information . Personal meetings may be held to give an agent his next assignment and instructions for carrying it out , to train him in tradecraft or the use of technical or communications equipment , to transmit documents , reports , technical equipment , money , or other items , or to fulfill several of these purposes . In actual practice several purposes are usually served by a meeting . In addition to its particular objectives more general needs can be filled . A meeting held for training purposes may be a means for clarifying biographic data on the agent or his views on various subjects . At every meeting with an agent one should study him and obtain new data on his potential and talents , thereby providing a better basis for judging his sincerity and deciding how much trust to place in him . Agents , to varying extents , need reinforcement . Salary is important and also gives a lever of compromise , although pressing it too hard can offend a truly ideologically motivated agent . Some agents benefit from recognition that they can never show , such as a uniform of your service , or decorations from it . Agents will be more comfortable if they believe that they will have protection , preferably exfiltration , if compromised . Protecting their families may be even more important . When the agent operates in a country with a particularly brutal counterintelligence service , providing them with a " final friend " , or means for suicide , can be comforting even if they never use it . Agent Communications . This section deals with skills required of individuals , either agents or support personnel . Most skills are concerned with communications . Meeting places for personal meetings . A Soviet officer commented , perhaps counterintuitively , that it is harder to have longer meetings with agents when the case officer is under diplomatic cover . The reason is that local counterintelligence is aware of the case officer , where the existence of an illegal ( i . e . , nonofficial cover in US terms ) officer may not be known to them . For the legal officer , " here it is best either to have reliable safehouses or to deliver the agent discreetly to the official residency building . The latter is a serious operational move . If neither is feasible , it is better to have Headquarters dispatch an officer to a third country , either legally or illegally , for the meeting . " Clandestine Transfer operated by Humans . It is a case - by - case decision whether the material exchanged should have safeguards against accessing it in other than a precise manner . One straightforward protection method is to have the material on exposed photographic film , in a container that does not suggest that it contains film and might be , innocently , opened in a lighted room . Self - destruct devices also are possibilities , but they confirm that the transfer involved sensitive material . Brush Pass and other physical exchange with couriers . Under the general term " brush pass " is a wide range of techniques in which one clandestine operative passes a physical item to another operative . During the brief contact , a common means of executing the exchange is for both to be carrying otherwise identical objects , such as a newspaper , briefcase , or magazine . The information being exchanged is in one of them . As the two people separate , they still appear to be holding the same object in the same hand . More challenging versions are reminiscent of passing a baton in a relay race , and would be most commonly done with small objects such as a photographic film cartridge . In this more dangerous method , the transfer is from hand to hand , or from hand into a pocket . While this technique obviously takes better manual dexterity and is more prone to error , it has the countersurveillance advantage that the operatives are not carrying anything after the transfer , and can blend into a crowd even more easily . A variation of the brush pass is the live letter drop , in which one agent follows a predefined route , on foot , with a prepared report hidden in a pocket . En route , a second agent unknown to the first agent picks his / her pocket and then passes the report on unread , either to a cut - out or to an intelligence officer . This technique presents opportunities both for plausible deniability and for penetration by hostile agents . Dead Drop . A dead drop is a container not easily found , such as a magnetized box attached to a metal rack in an out - of - sight alley . The box could be loosely buried . It should be possible to approach the container to fill or empty it , and not be easily observed from a street or window . Typically , a clandestine collector will put espionage material , perhaps in encrypted form , into the box , and use some prearranged signal to let a courier know that something needs to be taken out of the box and delivered to the next point on the route to the case officer . Such a route might have several dead drops . In some cases , the dead drop might be equipped with a device to destroy its contents unless it is opened properly . Signals to tell a courier , or a case officer if there is no intermediate courier , that the dead drop needs service can be as simple as a piece of colored tape on a lamp post or perhaps a set of window shades raised and lowered in a specific pattern . While " wrong number " calls with a predefined apology can be used , they are more vulnerable to surveillance if the phone in question is tapped . Car Tosses . A car toss can take many forms , one of which can be considered a moving dead drop . An agent or courier can put a magnetized box inside a bumper on a parked car . In some cases , if a car can drive slowly down a street or driveway not easily observed , a courier can toss a message container into an open window , making the transfer method intermediate between a brush pass and a dead drop . Cars with diplomatic immunity have advantages and disadvantages for tosses . They cannot be searched if the toss is observed , but they also are followed more easily . Diplomatic cars usually have distinctive markings or license plates , and may be equipped with electronic tracking devices . Counterintelligence could wait until the car is out of sight following a toss , then apprehend and interrogate the courier , or simply keep the courier under surveillance to discover another link in the message route . Methods of Protecting Message Content . A message left in a dead drop , or dropped during an improperly executed brush pass , is quite incriminating if counterintelligence personnel can immediately see suspicious information written on it . The ideal material for transfer looks quite innocuous . At one time , invisible ink , a subset of steganography , was popular in espionage communications , because it was not visible to the naked eye without development by heat or chemicals . While computer - based steganographic techniques still are viable , modern counterintelligence laboratories have chemical and photographic techniques that detect the disturbance of paper fibers by the act of writing , so the invisible ink will not resist systematic forensic analysis . Still , if its existence is not suspected , the analysis may not be done . Microphotography . Another technique , for hiding content that will resist casual examination , is to reduce the message to a photographic transparency or negative , perhaps the size of the dot over the letter " i " in this article . Such a technique needs both a laboratory and considerable technical skill , and is prone to damage and to accidentally falling off the paper . Still , it does have a countersurveillance value . Encryption . Encryption , especially using a theoretically secure method , when properly executed , such as the one - time pad , is highly secure , but a counterintelligence agent seeing nonsense characters will immediately become suspicious of the message that has been captured . The very knowledge that a dead drop exists can cause it to be trapped or put under surveillance , and the member of a brush pass that carries it will be hard - pressed to explain it . One - time pad encryption has the absolute requirement that the cryptographic key is used only once . Failure to follow this rule caused a serious penetration into Soviet espionage communications , through the VENONA analysis It is extremely difficult for a nonprofessional to develop a cryptosystem , especially without computer support , that is impervious to the attack by a professional cryptanalyst , working for an agency with government resources , such as the US NSA or Russian " Spetssvyaz " . Still , when the message is very short , the key is random or nearly random , some methods , like the Nihilist Straddling checkerboard may offer some resistance . Improvised methods are most useful when they only have to protect the information for a very short time , such as changing the location or time of an agent meeting scheduled in the same day . Plain language code . Less suspicious when examined , although very limited in its ability to transfer more than simple content , is plain language code . For example , the final attack order for the Battle of Pearl Harbor came in a radio broadcast of the Japanese phrase , " Climb Mount Niitaka " . Subsequent espionage communications referred to ships as different types of dolls at a doll repair shop . Plain language code is most effective when used to trigger a preplanned operation , rather than transfer any significant amount of information . Steganography , Covert Channels , and Spread Spectrum . Steganography , in the broadest sense of the word , is a technique of hiding information " in plain sight " within a larger message or messaging context . It is hard to detect because the secret message is a very small component of the larger amount , such as a few words hidden in a Web graphic . Even more sophisticated computer - dependent methods can protect information . The information may or may not be encrypted . In spread - spectrum communications , the information is sent , in parallel , at very low level through a set of frequencies . Only when the receiver knows the frequencies , the time relationship on when a given frequency or other communications channel will carry content , and how to extract the content , can information be recovered . Basic spread spectrum uses a fixed set of frequencies , but the signal strength in any one frequency is too low to detect without correlation to other frequencies . Frequency - hopping spread spectrum is a related technique , which can use the parallel transmission of true spread spectrum , not using any one frequency long enough for plausible interception . The pattern of variation among channels may be generated and received using crytographic methods . Methods of Protecting against Electronic Detection of the fact of messaging . Avoiding detection of radio signals means minimizing the clandestine transmitter ' s exposure to hostile direction - finding . Modern techniques generally combine several methods : Exploring agent information often meant a good deal of interaction , in which the home service would clarify what the agent reported , give new orders , etc . One approach used in WWII was the Joan - Eleanor system , which put the case officer into an aircraft at high altitude . From that altitude , there could be fast interaction in voice , so that they get to the key issues faster than with many separately encrypted and transmitted messages . The modern equivalent is a small , low probability of intercept radio transceiver , using a directional antenna aimed at an orbiting satellite communications relay . Avoiding detection of radio communications involves all the principles of transmission and reception security . Termination . For any number of reasons , a human source operation may need to be suspended for an indefinite time , or definitively terminated . This need rarely eliminates the need for protecting the fact of espionage , the support services , and the tradecraft and tools provided . One of the most difficult challenges is ending an emotional relationship between the case officer and agent , which can exist in both directions . Sometimes , an agent is unstable , and this is a major complication ; perhaps even requiring the evacuation of the agent . More stable agents may be happy with termination bonuses , and perhaps a future emigration opportunity , that do not draw attention to their own side ' s counterintelligence . In some instances , an intelligence agency may issue a " burn notice , " indicating to other such agencies that an individual is an unreliable source of information . Especially in the case of non - national organizations , termination can be very literal , ranging from having a trusted operative kill the problematic agent , or , when culturally appropriate , sending the agent on a suicide mission . When the clandestine phase is preparation for a DA mission such as the 9 / 11 attacks , or the assassination attacks , using suicide bombers , by the Liberation Tigers of Tamil Eelam , termination of the operational cells is rather obvious . If there are support cells in the operational area , they may be vulnerable , but it would be good tradecraft to withdraw them shortly before the attack . Special Clandestine Services . Agents of Influence . An agent of influence , being witting or unwitting of the goals of a foreign power B , can influence the policy of Country A to be consistent with the goals of Country B . In Soviet theory , influencing policy was one aspect of what they termed active measures ( " aktivnyye meropriyatiya " ) . Active measures have a different connotation than the Western concept of direct action ( DA ) , although Soviet active measures could include " wet affairs " ( " mokrie dela " ) conducted by Department V of the KGB , " wet " referring to the spilling of blood . Strategic deception . Intelligence organizations occasionally use live , or even dead , persons to deceive the enemy about their intentions . One of the best - known such operations was the British Operation Mincemeat , in which a dead body , bearing carefully misleading documents , was put in British uniform , and floated onto a Spanish beach . In WWII , Spanish security services , while officially neutral , often passed information to the Germans , which , in this case , is exactly what the British wanted done . This operation was under the control of the Twenty Committee , part of the British strategic deception organization , the London Controlling Section . A related British operation in WWI was run by a controversial military officer , Richard Meinertzhagen , who prepared a knapsack containing false military plans , which the Ottoman allies of the Germans were allowed to capture . The plans related to false British strategy for the Sinai and Palestine Campaign , setting up a successful surprise attack in the Battle of Beersheba and the Third Battle of Gaza . Active measures , however , reflected a national effort to influence other countries to act in concert with Soviet goals . These measures could involve state organizations up to and including the Politburo , much as the WWII British organization for strategic deception , the London Controlling Section , and its US counterpart , Joint Security Control , could get direct support from the head of government . Much of the Soviet responsibilities for active measures was focused in the KGB . Its " First Chief Directorate uses active measures such as agents of influence , propaganda , and disinformation to promote Soviet goals . " In the present political context of Western democracies , the sensitivity , and separation , of clandestine and open contacts do not lend themselves to the process of building agents of influence . " Active measures is not exclusively an intelligence activity , and in this sense it differs from the similar American concept of covert action . There are many differences between active measures and covert action . One is the Soviet ability to mesh overt and covert influence activities through centralized coordination of party , government , and ostensibly private organizations dealing with foreigners . Despite interagency coordination mechanisms , the United States is too pluralistic to achieve full coordination between all the overt and covert means of exercising influence abroad . Other major differences are in scope , intensity , and importance attributed to active measures and covert action , and in immunity from legal and political constraints . " While deception and influence operations could involve the highest levels of Allied governments in WWII , it is worth noting that while the West generally speaks of military deception , strategic deception operates at a higher level . A Soviet , and presumably Russian , term of art , " maskirovka " , is much broader than the current Western doctrine of deception being run by lower - level staff groups . In the military , responsibility for maskirovka easily can be at the level of a deputy chief of the General Staff , who can call upon all levels of government . Returning to KGB doctrine , presumably still present in the SVR , " Influence operations integrate Soviet views into foreign leadership groups . Propaganda operations take the form of disinformation articles placed in the foreign press . Disinformation operations are false documents designed to incite enmity toward the United States . " " The Second Chief Directorate " , whose responsibilities are now primarily in the Russian FSB , is responsible for the recruitment of agents among foreigners stationed in the Soviet Union . The KGB influences these people unwittingly , as most regard themselves too sophisticated to be manipulated . " The second deception program is counterintelligence , which aims to neutralize the efforts of foreign intelligence services . It achieves this through the use of non - Soviet double agents and Soviet double agents . Non - Soviet double agents are foreign nationals who have been " turned " . A Soviet double agent is a Soviet with access to classified information . These officials may be used as false defectors . . . " Influence operations integrate Soviet views into leadership groups . The agent of influence may be a well - placed , " trusted contact " who Direct Action Services . There is no consensus on whether it is , or is not , advisable to intermingle espionage and direct action organizations , even at the headquarters level . See Clandestine HUMINT and Covert Action for more history and detail . A terminology point : current US terminology , ignoring an occasional euphemism , has now consolidated espionage into the National Clandestine Services . These are part of the CIA Directorate of Operations , which has some responsibility for Direct Action ( DA ) and Unconventional Warfare ( UW ) , although the latter two , when of any appreciable size , are the responsibility of the military . There is much more argument for doing so at headquarters , possibly not as one unit but with regular consultation . Certain services , such as name checks , communications , cover identities , and technical support may reasonably be combined , although the requirements of a particular field network should be held on a need - to - know basis . Other countries might have the functions under the same organization , but run them in completely different networks . The only commonality they might have is emergency use of diplomatic facilities .