UNSUB

The term applied in espionage cases where the culprit has not been identified positively, from the Federal Bureau of Investigation abbreviation for “unidentified subject.”

UNIT 8200

The military intelligence cover designation of Israel’s signals intelligence organization which failed to interpret the increase in signal traffic between Damascus, Amman, and Cairo in 1973 as an indication of an imminent attack. Until recently commanded by Brigadier Pinhas Bulhris, Unit 8200 is responsible for all communications intelligence and cryptography and the development of new intercept techniques.

ULTRA

The classification assigned to signals intelligence emanating from intercepted enemy wireless traffic enciphered on the Enigma machine in 1942. Previously the code name had been BONIFACE. Later in the war ULTRA came to be used as a generic term and included other enemy cipher machines, such as the Siemens Geheimschreiber.

UKUSA

The acronym for the United Kingdom–United States of America Security Agreement signed in 1947 to enhance the BRUSA pact of May 1943, which set the terms for the exchange of signals intelligence between British and American cryptographic agencies.

U-BOAT

In both world wars, the German submarine fleet attempted to enforce a blockade on Great Britain, with the intention of starving the country into submission—and in both wars was prevented from doing so. The Kriegsmarine fleet suffered appalling losses during the Battle of the Atlantic, largely due to the skillful exploitation of enemy wireless traffic enciphered on the Enigma machine, along with Allied technical developments such as radar and sonar.
The German Type XXI diesel submarine, brought into service at the end of the war, proved to be an exceptional weapon at the time, and its design was adopted as the basis of the  Soviet Zulu and Whiskey classes, as well as the later Foxtrot class, the mainstay of the postwar Red Banner Fleet. Although noisy and easy to detect, a total of 75 Foxtrots were built before production ended in 1983. They were exported to India, Cuba, Libya, and Poland, and two were lost in accidents. The Foxtrot B-37 was lost in a torpedo explosion at Polnariy in 1962, and the B-33 sank off Vladivostok in 1991.

UB

The UB (Urzad Bezpieczenstwa/Security Office) was a shortened form of the official name Urzad Bezpieczenstwa Publicznego (Public Security Office), which was set up in early September 1944 in liberated territory of Poland by a team of NKVD agents parachuted into the country, later to be supervised by the NKVD  rezident, General Selianovsky, thereby setting a standard of surrogacy that was to be copied across Eastern Europe as the NKVD inserted its own personnel or nominees into the newly created security structures.
In July 1946 the Ministry of Public Security was divided into eight departments, of which five dealt with operational matters: I, Counterintelligence; II, Technical Operations and Technology; III, Anti-opposition; IV, Protection of the Economy; and V, Counterinfiltration and Counter-Church Influence. Early in 1948 Department VII, handling general intelligence, was created and in June the following year the powerful and highly secret Biuro do spraw Funkcjonariuszy (Officer’s Office) was set up as an internal counterintelligence section in order to maintain surveillance and investigate and control ministry personnel.
On 2 March 1950 the Biuro Specjalne (Special Office), which became Department X in November 1951, was established to provide surveillance and to investigate senior Communists and their cronies. At the peak of its power two years later, the security service employed 33,200 officers, with the Ministry of Public Security controlling 57,500 Citizens Militia (MO); 41,000 crack troops of the intensely loyal Korpus Bezpieczenstwa Wewnetrznego (KBW, Internal Security Corps); 32,000 Wojska Ochrony Pogranicza (WOP, Frontier Guards); and an armed Industry Guard (SP, Straz Przemyslowa) to protect industrial plants against sabotage. In addition the regime could rely on 10,000 Straz Wiezienna (SW) prison guards and the 125,000-strong Ochotnicza Rezerwa Milicji Obywatelskiej (ORMO, Citizen’s Militia Voluntary Reserve), which consisted of low-level informers who in emergencies were armed with batons or guns and deployed against unarmed protesters. All these despised plainclothesmen were known as “ubeks” by the general population, which did not distinguish between the security service and the rest.
After Josef Stalin’s death, the power of the Ministry of Public Security diminished and in June 1954 the feared Department X was disbanded, with other changes limited to the removal of a dozen or so most compromised officers. On 7 December 1954 the Ministry of Public Security was divided into the Ministerstwo Spraw Wewnetrznych (MSW, Ministry of Internal Affairs) and subordinated to the Komitet do spraw Bezpieczenstwa Publicznego (KBP, Cabinet Committee for Public Security). Thus the MSW gained control over the MO, ORMO, WOP, KBW, SP, and SW, leaving the KBP as a de facto security service operating independently and outside the departmental structure of the previous Ministry of Public Security.
In September 1955 the KBP was reinforced by an amalgamation of the Informacja Wojskowa (Military Intelligence and Counterintelligence Service) and the Wojska Wewnetrzne, an internal military unit designed to prevent mutiny within the armed forces. Previously both had been subordinate to the Ministry of National Defense, but no announcement was made to explain the extension of the KBP’s power.
An order made in September 1955 committed the security service to support Informaca Wojskowa, and vice versa. Following the Twentieth Party Congress in Moscow, at which Nikita Khrushchev denounced Stalin, and the Poznan riots, the Polish Communist party disbanded the KBP as of November 1956. The Public Security Offices (UBPs) were dismantled and the hitherto informal security service was reduced in number and power, streamlined, and incorporated into Polish Ministry of Internal Affairs (MSW), where it was named officially the Security Service, the Sluzba Bezpieczenstwa (SB); the nickname “ubek” was so deeply rooted in the public mind, however, that it survived despite some competition from the new acronym “esbek.”

U-2

The designation of the aircraft built by Lockheed for the Central Intelligence Agency as a high-altitude, single-engine reconnaissance aircraft. It flew for the first time in August 1955. The following year U-2s began overflights of  Soviet territory from Adana in Turkey, Lakenheath in England, and Giebelstadt in Germany, concentrating on the missile test sites at Kapustin Yar and Tyuratam. Following the destruction of a U-2 near Sverdlovsk in May 1960, and the capture of its CIA pilot, Francis Gary Powers, President Dwight D. Eisenhower banned further intrusions into Soviet airspace. Altogether two American U-2 planes were shot down, the other being a flight over Cuba in October 1962, killing the pilot, Maj. Rudolf Anderson. In addition, six Taiwanese U-2s were destroyed over the Peoples’ Republic of China between 1962 and 1969.
The  imagery captured by the U-2 overflights, processed by the National Photographic Interpretation Center (NPIC) and code-named IDEALIST, was considered invaluable, serving to undermine the “bomber gap” theory. It was later replaced by photographs from CORONA satellites beginning in August 1960 and from SR-71 Blackbirds in January 1964. A total of 106 U-2s were built, and it remains an effective surveillance aircraft, still in service around the globe.