Gardening (cryptanalysis)
Encyclopedia
In cryptanalysis
, gardening was a term used at Bletchley Park
, England, during World War II
for schemes to entice the Germans to include known plaintext, which the British called "cribs," in their encrypted messages. This term presumably came from RAF minelaying missions, or “gardening” sorties, so called because sectors of the coastal waters around Europe were given code-names based on fruits and vegetables. The technique is claimed to have been most effective against messages produced by the German Navy's Enigma machine
s.
A well-known example involved mine
s. If the Germans had recently swept a particular area for mines, and Bletchley Park
was in need of some cribs, they might (and apparently did on several occasions) direct that the area be mined again. This would hopefully evoke encrypted messages from the local command mentioning 'Minen' ('mines' in German) and/or the location, and perhaps messages also from the headquarters with minesweeping ships to assign to that location, mentioning the same. It worked often enough to try several times. In modern terms, this was a chosen plaintext attack, because plain text effectively chosen by the British was injected into the ciphertext.
Cryptanalysis
Cryptanalysis is the study of methods for obtaining the meaning of encrypted information, without access to the secret information that is normally required to do so. Typically, this involves knowing how the system works and finding a secret key...
, gardening was a term used at Bletchley Park
Bletchley Park
Bletchley Park is an estate located in the town of Bletchley, in Buckinghamshire, England, which currently houses the National Museum of Computing...
, England, during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
for schemes to entice the Germans to include known plaintext, which the British called "cribs," in their encrypted messages. This term presumably came from RAF minelaying missions, or “gardening” sorties, so called because sectors of the coastal waters around Europe were given code-names based on fruits and vegetables. The technique is claimed to have been most effective against messages produced by the German Navy's Enigma machine
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...
s.
A well-known example involved mine
Naval mine
A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...
s. If the Germans had recently swept a particular area for mines, and Bletchley Park
Bletchley Park
Bletchley Park is an estate located in the town of Bletchley, in Buckinghamshire, England, which currently houses the National Museum of Computing...
was in need of some cribs, they might (and apparently did on several occasions) direct that the area be mined again. This would hopefully evoke encrypted messages from the local command mentioning 'Minen' ('mines' in German) and/or the location, and perhaps messages also from the headquarters with minesweeping ships to assign to that location, mentioning the same. It worked often enough to try several times. In modern terms, this was a chosen plaintext attack, because plain text effectively chosen by the British was injected into the ciphertext.