Al Cimino - The Story of Codebreaking

Thomas Phelippes worked for Sir Francis Walsinghams counter-intelligence network, set up to protect the government of Queen Elizabeth I. Phelippes broke the secret code used by Mary Queen of Scots, leading to her execution, and also unmasked the conspirators in the Gunpowder Plot.

In North America, a mechanical ciphering system was invented by Thomas Jefferson. Other forms were developed during the American Civil War. Also in the 19th century, scientists such as Charles Wheatstone and Charles Babbage, pioneer of the computer, devoted much time and effort to devising and breaking codes. It is thought that Babbages codebreaking system was used during the Crimean War. Meanwhile, codebreaking methods were being used to decipher long-forgotten languages such as Egyptian hieroglyphics and Linear B.

Britains interception and decoding of the Zimmermann telegram, which revealed Germanys battle plans, brought the USA into World War I. Then, in the 1920s, the US government repudiated the use of codebreaking as ungentlemanly. This left America hopelessly unprepared when war threatened again in the following decade. An intercept that could have warned of the Japanese attack on Pearl Harbor was not decoded in time. Later in World War II, heroic efforts by American cryptologists broke the Japanese naval codes and gave the US Navy the upper hand in the Battle of Midway, which eventually led to victory in the Pacific.

Germany had gone into World War II believing it had an unbreakable code Enigma not knowing that three inspired Polish codebreakers had already deciphered it before hostilities had even broken out. The Poles passed their expertise and early codebreaking machines on to the British, who used them to good effect throughout the war, and especially in the Battle of Britain and at El Alamein (the latter turned the tide against the German Army in North Africa).

At the British codebreaking centre at Bletchley Park, Alan Turing developed methods and machinery bequeathed by Polish cryptologists to break the more complex Naval Enigma. This thwarted the German U-boats that were threatening to starve Britain into surrender.