The Sigint Secrets - The Signals Intelligence War 1900 to Today

At the beginning of the twentieth century, spies still carried invisible ink, wore questionable moustaches and occasionally concealed documents inside objects no customs officer wished to examine closely. Then governments discovered that vast quantities of secret information were travelling invisibly through the air, and espionage acquired headphones, aerials, codebooks and entire buildings filled with people listening to static. In The SIGINT Secrets , Nigel West traces the development of signals intelligence from the early days of wireless communication to the electronic surveillance systems of the late Cold War. SIGINT?because even secrecy requires an efficient abbreviation?covers the interception and analysis of communications and other electronic signals. It is the art of learning what an opponent is doing by listening to messages he believed nobody else could understand. The book begins around 1900, when radio promised to liberate communication from cables while inadvertently allowing anyone with suitable equipment to listen. Naval and military commanders embraced wireless because it was fast and flexible. Intelligence officers embraced it because the enemy had kindly begun broadcasting information in all directions. West follows British signals intelligence through the First World War, when Room 40 of the Admiralty intercepted and decrypted German naval communications. The work contributed to operations such as the Battle of Jutland and produced the famous Zimmermann Telegram, whose revelation helped bring the United States into the war. A message intended to remain confidential had instead altered international history, establishing an enduring relationship between new communication technology and regrettable surprises. Between the wars, British codebreaking became institutionalised within the Government Code and Cypher School. Cryptanalysts, linguists, radio operators and administrators developed the systems that would become indispensable during the Second World War. The organisation?s name sounded reassuringly like an educational establishment where one might be awarded a certificate; its actual purpose was to read other governments? mail without requesting permission. Bletchley Park naturally occupies an important part of the story. Here, British and Allied personnel attacked German cipher systems, including Enigma, while the wider network of intercept stations gathered the messages upon which the codebreakers depended. The popular image features a solitary genius solving an impossible puzzle; the reality involved mathematics, engineering, traffic analysis, thousands of operators and an industrial quantity of clerical work. West explains that signals intelligence extends beyond breaking codes. Direction-finding could reveal the location of transmitters, traffic analysis could expose the structure and movements of enemy units, and patterns of communication could disclose information even when the messages themselves remained unreadable. Silence might also be significant. Intelligence analysts therefore became experts in extracting meaning from what was said, how it was said, where it came from and why somebody had suddenly stopped saying it. The book challenges simplified versions of the Allied assault on Enigma, showing that success was neither immediate nor permanent. Codes changed, procedures improved and access to particular networks came and went. A cipher might be penetrated only for the enemy to alter a setting and restore darkness. Codebreaking was less like finding one magical key than operating a locksmith?s shop during an earthquake. After 1945, the Government Code and Cypher School became Government Communications Headquarters?GCHQ?and the wartime alliance with American intelligence developed into an enormous Cold War partnership. The targets changed from Nazi Germany and Japan to the Soviet Union and its allies, while interception expanded across radio, telephone, radar and satellite communications. The.…