Title: Solving the Enigma
Author: Jennifer Wilcox
Wilcox, Jennifer (2006). Solving the Enigma: History of the Cryptanalytic Bombe. Fort George G. Meade, MD: Center for Cryptologic History, National Security Agency
LCCN: Not available
Date Updated: August 24, 2015
This brochure was produced at the Cryptographic History Center of NSA, and may be downloaded from their web site. It is 60 pages in length, too long to reproduce here in its entirety.
Wilcox does an excellent summary of the Enigma bombe in this brochure (really a monograph). She describes how the German Enigma enciphering machine was broken by the British bombe—the cryptanalytical machine designed by Alan Turing and Gordon Welchman at Bletchley Park, the center of Allied codebreaking during World War II.
The bombes were neither the only, nor the first, method of breaking the Enigma but the breaks facilitated by the bombes from 1940 onwards yielded intelligence in a quantity unprecedented in military history and made a major contribution to Allied victory.
The Enigma was not the only enciphering machine employed by Germany in World War II. The other machines, the Siemens T52 Geheimschreiber and the Lorenz SZ40/SZ42 Schlüsselzusatz were codenamed STURGEON and TUNNY respectively at Bletchley Park. The traffic derived from TUNNY was known at Bletchley Park as FISH. TUNNY was initially broken by hand methods due to an extraordinary German error and later with the assistance of Heath Robinson, an experimental punched paper tape comparator incorporating about 30 valves. Having shown the comparison method of cryptanalysis to be workable, a second, more practical machine, called Colossus, was designed to break the FISH machines. Colossus was arguably the world’s first electronic computer and incorporated about 1600 valves.
The cornucopia of intelligence gleaned from the Enigma breaks and from FISH was known as ULTRA.
The monograph contains a number of pictures of the technology and the people involved, and charts of encrypting/decrypting. It is an essential document to anyone studying Enigma.