Despite publicity given to the successes of British and American codebreakers during the Second World War, the study of signals intelligence is still complicated by governmental secrecy over even the most elderly peacetime sigint. This book, first published in 1986, lifts the veil on some of these historical secrets. Christopher Andrew and Keith Neilson cast new light on how Tsarist codebreakers penetrated British code and cypher systems. John Chapman’s study of German military codebreaking represents a major advance in our understanding of cryptanalysis during the Weimar Republic. The history of the Government Code and Cypher School – forerunner of today’s GCHQ – by its operational head, the late A.G. Denniston, provides both a general assessment of the achievements of British cryptanalysis between the wars and a tantalising glimpse of what historians may one day find in GCHQ’s forbidden archives. The distinguished cryptanalyst of Bletchley Park, the late Gordon Welchman, describes in detail how the Ultra programme defeated the German Enigma machine, while another Bletchley Park cryptographer, Christopher Morris, reminds us in his account of the valuable work on hand cyphers that wartime sigint consisted of much more than Ultra. Roger Austin’s study of surveillance under the Vichy regime shows the continuing importance of older and simpler methods of message interception such as letter-opening. Taken together, the articles establish sigint as an essential field of study for both the modern historian and the political scientist.

In Code Warriors, Stephen Budiansky--a longtime expert in cryptology--tells the fascinating story of how NSA came to be, from its roots in World War II through the fall of the Berlin Wall. Along the way, he guides us through the fascinating challenges faced by cryptanalysts, and how they broke some of the most complicated codes of the twentieth century. With access to new documents, Budiansky shows where the agency succeeded and failed during the Cold War, but his account also offers crucial perspective for assessing NSA today in the wake of the Edward Snowden revelations. Budiansky shows how NSA's obsession with recording every bit of data and decoding every signal is far from a new development; throughout its history the depth and breadth of the agency's reach has resulted in both remarkable successes and destructive failures.

The untold story of Bletchley Park's key role in the success of the Normandy campaign Since the secret of Bletchley Park was revealed in the 1970s, the work of its codebreakers has become one of the most famous stories of the Second World War. But cracking the Nazis' codes was only the start of the process. Thousands of secret intelligence workers were then involved in making crucial information available to the Allied leaders and commanders who desperately needed it. Using previously classified documents, David Kenyon casts the work of Bletchley Park in a new light, as not just a codebreaking establishment, but as a fully developed intelligence agency. He shows how preparations for the war's turning point--the Normandy Landings in 1944--had started at Bletchley years earlier, in 1942, with the careful collation of information extracted from enemy signals traffic. This account reveals the true character of Bletchley's vital contribution to success in Normandy, and ultimately, Allied victory.

To defeat your enemies you must know them well. In wartime, however, enemy codemakers make that task much more difficult. If you cannot break their codes and read their messages, you may discover too late the enemy's intentions. That's why codebreakers were considered such a crucial weapon during World War II. In Secret Messages, David Alvarez provides the first comprehensive analysis of the impact of decoded radio messages (signals intelligence) upon American foreign policy and strategy from 1930 to 1945. He presents the most complete account to date of the U.S. Army's top-secret Signal Intelligence Service (SIS): its creation, its struggles, its rapid wartime growth, and its contributions to the war effort. Alvarez reveals the inner workings of the SIS (precursor of today's NSA) and the codebreaking process and explains how SIS intercepted, deciphered, and analyzed encoded messages. From its headquarters at Arlington Hall outside Washington, D.C., SIS grew from a staff of four novice codebreakers to more than 10,000 people stationed around the globe, secretly monitoring the communications of not only the Axis powers but dozens of other governments as well and producing a flood of intelligence. Some of the SIS programs were so clandestine that even the White House—unaware of the agency's existence until 1937—was kept uninformed of them, such as the 1943 creation of a super-secret program to break Soviet codes and ciphers. In addition, Alvarez brings to light such previously classified operations as the interception of Vatican communications and a comprehensive program to decrypt the communications of our wartime allies. He also dispels many of the myths about the SIS's influence on American foreign policy, showing that the impact of special intelligence in the diplomatic sphere was limited by the indifference of the White House, constraints within the program itself, and rivalries with other agencies (like the FBI). Drawing upon military and intelligence archives, interviews with retired and active cryptanalysts, and over a million pages of cryptologic documents declassified in 1996, Alvarez illuminates this dark corner of intelligence history and expands our understanding of its role in and contributions to the American effort in World War II.

Central Bureau - Australia's own large and sophisticated intelligence network, built from scratch. It was this group of mathematicians, code-breakers, and radio experts who intercepted the travel plans of the architect of the Pearl Harbor attack, Admiral Yamamoto, leading to his ambush and death. Australian signals intelligence also played a vital role in the battles of the Coral Sea, Milne Bay, Hollandia, and many others. General Douglas MacArthur, the supreme commander of the local Allied forces, went so far as to insist that the men of Central Bureau accompany him on his counter-attack in the Pacific. After the war, the US sought to give these non-combatants the highest awards possible - honours that were suppressed by the Australian government in their need for secrecy. A groundbreaking work of military history, The Secret Code-breakers of Central Bureau gives these talented and dedicated individuals their due at last. It is a rich account of the shadowy side of military strength and of the men and women whose work was, in the words of the US navy, of 'immeasurable importance in the successfulmprosecution' of the Pacific War. 'Who knew? This enthralling study tells a deeply human story. The men and women who gave our troops a significant edge in the fight against the Japanese are the genuine heroes in this engaging and exciting book.' -Michael McKernan, author of The Strength of a Nation and When This Thing Happened 'This is history and military strategy written at its most engaging.' -Waikato Times 'A delightfully and thoroughly engaging story of the emergence of the Australian contribution to the signals and radio interception intelligence ... Dufty's writing style is light and easy to read, reminiscent of other contemporary historical narratives that tell a series of stories, most notably the emphasis of the human story associated with these experiences.' -Rhys Ball, NZ International Review

The award-winning New York Times bestseller about the American women who secretly served as codebreakers during World War II--a "prodigiously researched and engrossing" (New York Times) book that "shines a light on a hidden chapter of American history" (Denver Post). Recruited by the U.S. Army and Navy from small towns and elite colleges, more than ten thousand women served as codebreakers during World War II. While their brothers and boyfriends took up arms, these women moved to Washington and learned the meticulous work of code-breaking. Their efforts shortened the war, saved countless lives, and gave them access to careers previously denied to them. A strict vow of secrecy nearly erased their efforts from history; now, through dazzling research and interviews with surviving code girls, bestselling author Liza Mundy brings to life this riveting and vital story of American courage, service, and scientific accomplishment.

Despite publicity given to the successes of British and American codebreakers during the Second World War, the study of signals intelligence is still complicated by governmental secrecy over even the most elderly peacetime sigint. This book, first published in 1986, lifts the veil on some of these historical secrets. Christopher Andrew and Keith Neilson cast new light on how Tsarist codebreakers penetrated British code and cypher systems. John Chapman’s study of German military codebreaking represents a major advance in our understanding of cryptanalysis during the Weimar Republic. The history of the Government Code and Cypher School – forerunner of today’s GCHQ – by its operational head, the late A.G. Denniston, provides both a general assessment of the achievements of British cryptanalysis between the wars and a tantalising glimpse of what historians may one day find in GCHQ’s forbidden archives. The distinguished cryptanalyst of Bletchley Park, the late Gordon Welchman, describes in detail how the Ultra programme defeated the German Enigma machine, while another Bletchley Park cryptographer, Christopher Morris, reminds us in his account of the valuable work on hand cyphers that wartime sigint consisted of much more than Ultra. Roger Austin’s study of surveillance under the Vichy regime shows the continuing importance of older and simpler methods of message interception such as letter-opening. Taken together, the articles establish sigint as an essential field of study for both the modern historian and the political scientist.

A fascinating new work that challenges preconceptions of both Bletchley Park and organization studies.

This book reveals the historical context and the evolution of the technically complex Allied Signals Intelligence (Sigint) activity against Japan from 1920 to 1945. It traces the all-important genesis and development of the cryptanalytic techniques used to break the main Japanese Navy code (JN-25) and the Japanese Army’s Water Transport Code during WWII. This is the first book to describe, explain and analyze the code breaking techniques developed and used to provide this intelligence, thus closing the sole remaining gap in the published accounts of the Pacific War. The authors also explore the organization of cryptographic teams and issues of security, censorship, and leaks. Correcting gaps in previous research, this book illustrates how Sigint remained crucial to Allied planning throughout the war. It helped direct the advance to the Philippines from New Guinea, the sea battles and the submarine onslaught on merchant shipping. Written by well-known authorities on the history of cryptography and mathematics, Code Breaking in the Pacific is designed for cryptologists, mathematicians and researchers working in communications security. Advanced-level students interested in cryptology, the history of the Pacific War, mathematics or the history of computing will also find this book a valuable resource.

The story of Bletchley Park, the successful intelligence operation that cracked Germany's Enigma Code. Photos.