Cipher

Cipher (pronounced sahy-fer)

(1) Zero (archaic).

(2) Any of the Arabic numerals or figures (historic use only).

(3) To use figures or numerals arithmetically (historic use only).

(4) To write in or as in cipher.

(5) To calculate numerically; figure (historic use only).

(6) To convert into cipher.

(7) A numeric character (historic use only).

(8) Any text character (historic use only).

(9) A combination or interweaving of letters, as the initials of a name; a device; a monogram.

(10) A method of transforming a text in order to conceal its meaning.

(11) In cryptography, a system using an algorithm that converts letters or sequences of bits into cipher-text.

(12) A grouping of three digits in a number, especially when delimited by commas or periods.

(13) In music, a fault in an organ valve which causes a pipe to sound continuously without the key having been pressed.

(14) In music, slang for a hip-hop jam session (although some etymologists thing this is wholly unrelated to cipher’s accepted lineage.

(15) The path (usually vaguely circular) shared cannabis takes through a group.

(16) Someone or something of no importance.

(17) As cipher.exe, an external filter command in some versions of Microsoft operating systems, used to encrypt and decrypt data on drives using HPFS (High-Performance File System & NTFS (New Technology File System).

Late 1300s: From the Middle English siphre & cifre, from the Old French cyfre & cyffre (nought, zero) (which endures in Modern French as chiffre) from the Medieval Latin cifra & ciphra, (like the Spanish and Italian cifra), ultimately from the Arabic صِفْر‎ (ṣifr) (zero, empty), from صَفَرَ‎ (ṣafara) (to be empty), a loan-translation of the Sanskrit śūnyā-s (empty) The alternative spelling is cypher.  The word came to Europe in the twelfth century with the arrival of Arabic numerals.  Meaning first "zero", by the fifteenth century it had come to mean "any numeral" and then, following the use in French & Italian, "secret way of writing; coded message", a sense which in English emerged by the 1520s, the origin of the shift being the early diplomatic codes, often creations which substituted numbers for letters.  The meaning "the key to a cipher or secret writing" was by 1885 short for “cipher key”, a phrase in use since 1835.  Drawing from the sense of “zero”, the figurative sense of "something or someone of no value, consequence, or power" dates from the 1570s.

The verb in the sense of “doing arithmetic" (with Arabic numerals) emerged in the 1520s and was derived from the noun while the transitive sense (reckon in figures, cast up) was first noted in 1860 and the specific sense of a cipher code being something which might be associated with the occult characters was first attested in 1563.  The verb decipher (an obviously essential companion to cipher) in the 1520s had a now obsolete meaning in mathematics (find out, discover) but by the 1540s it meant "interpret” in the sense of rendering a coded message (a cipher) back into the language or origin by use of a cipher-key.  It may, at least in part, be a loan-translation from the French déchiffrer.  From circa 1600, it moved beyond the literal to the transferred sense of "discover or explain the meaning of what is difficult to understand", the sense of "succeed in reading what is written in obscure or partially obliterated characters" used by 1710.  Cipher is a noun & verb; ciphering is a noun; the noun plural is ciphers.

German Enigma M4 encryption machine.  Introduced for commercial purposes in 1923, it was used by the German Navy from 1926, all branches of the service adopting it by 1935.  Built initially with three rotors, a fourth was added in 1941.

Although used by the Wehrmacht (the German armed forces) throughout the war, work by Polish mathematicians, aided by French intelligence, had enabled Polish cryptographers to break the codes and thus read German military traffic between 1932-1938, at which point additional layers of complexity were added.  In 1939, as war approached, the Poles passed their work to the allies where the code-breaking continued, culminating in the “Ultra” decrypts which would be of such value during the war.

The text "Lindsay Lohan" encrypted using different ciphers:

Standard Vigenère cipher: Nzlslig Nffpg
Beaufort cipher: Rjlmbik Rdrpg
Variant Beaufort cipher: Jrpozsq Jxjlu
Trithemius cipher: Ljpgwfe Swqky

In the decryption process, the British made some of the first use at scale of electronic computers and so secret was the project regarded that the protocols of the existing highest level of secrecy in the machinery of government, “Most Secret”, was thought inadequate and “Ultra Secret” was thus created with a tiny distribution list.  Also deployed was the coat-and-dagger trick of the misleading code-name Boniface, used in a way to convey the impression the British had a master spy they called “Boniface” controlling a network of spies throughout the political, military and industrial structures of the Reich.  The ruse proved successful, the OKM (Oberkommando der Marine; the German naval high command) never taking seriously the suggestion their codes had been broken, instead repeatedly combing their organisation for spies.  The existence of the British code-breaking project and the volume and importance of the Ultra decrypts to the war effort wasn’t widely known until an (at times misleading) account was published  in 1974 in The Ultra Secret by a former RAF officer, FW Winterbotham (1897-1990).  Although criticised in detail, what was revealed did compel a re-evaluation of some of the conclusions drawn by historians about political and military matters during the war.