Card catalog (cryptology)
Encyclopedia
The card catalog, or "catalog of characteristics," in cryptography
, was a system designed by Polish
Cipher Bureau
mathematician-cryptologist Marian Rejewski
, and first completed about 1935 or 1936, to facilitate decrypting German Enigma
cipher
s.
that Rejewski had invented about 1934 or 1935, was a laborious task that took over a year's time. But once the catalog was complete, obtaining Enigma daily keys was a matter of some fifteen minutes.
When the Germans changed the Enigma machine's "reflector
," or "reversing drum," on November 1, 1937, the Cipher Bureau was forced to start over again and produce a new card catalog, "a task," writes Rejewski, "which consumed, on account of our greater experience, probably somewhat less than a year's time."
On September 15, 1938, the Germans changed entirely the procedure for enciphering message keys, and as a result the card-catalog method became completely useless. This spurred the invention of Rejewski's cryptologic bomb
and Henryk Zygalski
's "perforated sheets
."
Cryptography
Cryptography is the practice and study of techniques for secure communication in the presence of third parties...
, was a system designed by Polish
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
Cipher Bureau
Biuro Szyfrów
The Biuro Szyfrów was the interwar Polish General Staff's agency charged with both cryptography and cryptology ....
mathematician-cryptologist Marian Rejewski
Marian Rejewski
Marian Adam Rejewski was a Polish mathematician and cryptologist who in 1932 solved the plugboard-equipped Enigma machine, the main cipher device used by Germany...
, and first completed about 1935 or 1936, to facilitate decrypting German Enigma
Enigma machine
An Enigma machine is any of a family of related electro-mechanical rotor cipher machines used for the encryption and decryption of secret messages. Enigma was invented by German engineer Arthur Scherbius at the end of World War I...
cipher
Cipher
In cryptography, a cipher is an algorithm for performing encryption or decryption — a series of well-defined steps that can be followed as a procedure. An alternative, less common term is encipherment. In non-technical usage, a “cipher” is the same thing as a “code”; however, the concepts...
s.
History
Preparation of the card catalog, using the cyclometerCyclometer
The cyclometer was a cryptologic device designed, "probably in 1934 or 1935," by Marian Rejewski of the Polish Cipher Bureau's German section to facilitate decryption of German Enigma ciphertext.-History:...
that Rejewski had invented about 1934 or 1935, was a laborious task that took over a year's time. But once the catalog was complete, obtaining Enigma daily keys was a matter of some fifteen minutes.
When the Germans changed the Enigma machine's "reflector
Reflector (cipher machine)
A reflector, in cryptology, is a component of some rotor cipher machines, such as the Enigma machine, that sends electrical impulses that have reached it from the machine's rotors, back in reverse order through those rotors.- Other names :...
," or "reversing drum," on November 1, 1937, the Cipher Bureau was forced to start over again and produce a new card catalog, "a task," writes Rejewski, "which consumed, on account of our greater experience, probably somewhat less than a year's time."
On September 15, 1938, the Germans changed entirely the procedure for enciphering message keys, and as a result the card-catalog method became completely useless. This spurred the invention of Rejewski's cryptologic bomb
Bomba (cryptography)
The bomba, or bomba kryptologiczna was a special-purpose machine designed about October 1938 by Polish Cipher Bureau cryptologist Marian Rejewski to break German Enigma-machine ciphers....
and Henryk Zygalski
Henryk Zygalski
Henryk Zygalski was a Polish mathematician and cryptologist who worked at breaking German Enigma ciphers before and during World War II.-Life:...
's "perforated sheets
Perforated sheets
The method of Zygalski sheets was a cryptologic technique used by the Polish Cipher Bureau before and during World War II, and during the war also by British cryptologists at Bletchley Park, to decrypt messages enciphered on German Enigma machines....
."