Cryptanalysis refers to the process of analyzing information systems in order to understand hidden aspects of the systems. Cryptanalysis is used to breach cryptographic security systems and gain access to the contents of encrypted messages, even if the cryptographic key is unknown.
Communications security is the discipline of preventing unauthorized interceptors from accessing telecommunications in an intelligible form, while still delivering content to the intended recipients.
Defence Intelligence (DI) is an organisation within the United Kingdom intelligence community which focuses on gathering and analysing military intelligence. It differs from the UK's intelligence agencies in that it is an integral part of a government department – the Ministry of Defence (MoD) – rather than a stand-alone organisation. The organisation employs a mixture of civilian and military staff and is funded within the UK's defence budget. The organisation was formerly known as the Defence Intelligence Staff (DIS), but changed its name in 2009.
Cryptography, the use of codes and ciphers to protect secrets, began thousands of years ago. Until recent decades, it has been the story of what might be called classical cryptography — that is, of methods of encryption that use pen and paper, or perhaps simple mechanical aids. In the early 20th century, the invention of complex mechanical and electromechanical machines, such as the Enigma rotor machine, provided more sophisticated and efficient means of encryption; and the subsequent introduction of electronics and computing has allowed elaborate schemes of still greater complexity, most of which are entirely unsuited to pen and paper.
Brigadier John Hessell Tiltman, was a British Army officer who worked in intelligence, often at or with the Government Code and Cypher School (GC&CS) starting in the 1920s. His intelligence work was largely connected with cryptography, and he showed exceptional skill at cryptanalysis. His work in association with Bill Tutte on the cryptanalysis of the Lorenz cipher, the German teleprinter cipher, called "Tunny" at Bletchley Park, led to breakthroughs in attack methods on the code, without a computer. It was to exploit those methods, at extremely high speed with great reliability, that Colossus, the first digital programmable electronic computer, was designed and built.
The Intelligence Bureau (IB) is India's internal security and counter-intelligence agency under Ministry of Home Affairs. It was founded in 1887 as Central Special Branch, and is reputed to be the oldest such organization in the world.
Law enforcement in India is imperative to keeping justice and order in the nation. Indian law is enforced by a number of agencies. Unlike many federal nations, the constitution of India delegates the maintenance of law and order primarily to the states and territories.
Cryptography was used extensively during World War II because of the importance of radio communication and the ease of radio interception. The nations involved fielded a plethora of code and cipher systems, many of the latter using rotor machines. As a result, the theoretical and practical aspects of cryptanalysis, or codebreaking, were much advanced.
The Directorate General of Forces Intelligence, commonly known as DGFI, is the military intelligence agency of the Bangladesh Armed Forces, tasked with collection, collation and evaluation of strategic and topographic information, primarily through human intelligence (HUMINT). As one of the principal members of the Bangladesh intelligence community, the DGFI reports to the Director-General and is primarily focused on providing intelligence for the Prime Minister, the Cabinet of Bangladesh, and the Armed Forces of Bangladesh.
The Directorate of Revenue Intelligence (DRI) is an Indian intelligence agency. It is India's apex anti-smuggling intelligence, investigations and operations agency.
With the rise of easily-intercepted wireless telegraphy, codes and ciphers were used extensively in World War I. The decoding by British Naval intelligence of the Zimmermann telegram helped bring the United States into the war.
The Deuxième Bureau de l'État-major général was France's external military intelligence agency from 1871 to 1940. It was dissolved together with the Third Republic upon the armistice with Germany. However the term "Deuxième Bureau", like "MI6" and "KGB", outlived the original organization as a general label for the country's intelligence service.
The following outline is provided as an overview of and topical guide to cryptography:
The Defence Intelligence Agency (DIA) is an intelligence agency responsible for providing and coordinating defence and military intelligence to the Indian Armed Forces.
The Cipher Department of the High Command of the Wehrmacht was the Signal Intelligence Agency of the Supreme Command of the Armed Forces of the German Armed Forces before and during World War II. OKW/Chi, within the formal order of battle hierarchy OKW/WFsT/Ag WNV/Chi, dealt with the cryptanalysis and deciphering of enemy and neutral states' message traffic and security control of its own key processes and machinery, such as the rotor cipher machine ENIGMA machine. It was the successor to the former Chi bureau of the Reichswehr Ministry.
The Government of the United Kingdom maintains several intelligence agencies that deal with secret intelligence. These agencies are responsible for collecting, analysing and exploiting foreign and domestic intelligence, providing military intelligence, and performing espionage and counter-espionage. Their intelligence assessments contribute to the conduct of the foreign relations of the United Kingdom, maintaining the national security of the United Kingdom, military planning, public safety, and law enforcement in the United Kingdom. The four main agencies are the Secret Intelligence Service, the Security Service (MI5), the Government Communications Headquarters (GCHQ) and Defence Intelligence (DI). The agencies are organised under three government departments, the Foreign Office, the Home Office and the Ministry of Defence.
The Research Office of the Reich Air Ministry was the signals intelligence and cryptanalytic agency of the German Nazi Party from 1933 to 1945. Run since its inception by Luftwaffe chief Hermann Göring, the Research Bureau was a Nazi Party institution rather than an official Wehrmacht-run military signals intelligence and cryptographic agency.
The Pers Z S was the signals intelligence agency of the German Foreign Office before and during World War II. It consisted of two cryptologic sections. Pers Z S was the cryptanalytic section which was called Special Service of Z Branch of the Foreign Office Personnel Department. Its mission was the solution of foreign diplomatic codes and ciphers. The other section, which was the Cryptography Section was called Personal Z Cipher Service of the Federal Foreign Office. The latter section was responsible for compilation, distribution and security of Foreign Office codes and ciphers. Both were colloquially known as Pers Z S. Though similar in nature and operation to the OKW/Chi cipher bureau, it was a civilian operation as opposed to the military operation at OKW/Chi and focused primarily on diplomatic communications. According to TICOM interrogators it evinced an extraordinary degree of competence, primarily driven by a consistency of development not found in any other German signals bureau of the period. Pers Z S/Chi was the symbol and the code name of the Chiffrierdienst, i.e. the Cryptanalysis Department of Pers Z S. Although little is known about the organization, in the final analysis, Pers Z S labored at diplomatic cryptanalysis for a regime for which there were no diplomatic solutions.
Wilhelm Fenner was a German cryptanalyst, before and during the time of World War II in the OKW/Chi, the Cipher Department of the High Command of the Wehrmacht, working within the main cryptanalysis group, and entrusted with deciphering enemy message traffic (Cryptography). Wilhelm Fenner was considered an excellent organizer, an anti-Nazi, an anti-Bolshevik and a confirmed Protestant and was known by colleagues as someone who was keen to continue working in cryptology after World War II. To quote military historian David Alvarez:
