TERMIUM Plus^®

Fiche 1,  Justifications,  Anglais

Record number: 1, Textual support number: 1 DEF

... a statistical measure of text which distinguishes text encrypted with a simple substitution cipher(also known as a monoalphabetic cipher) and more complicated Vigenere methods(polyalphabetic ciphers.) It was discovered by Phillip Friedman... To determine the index of coincidence of a piece of text, take the text and shift it by some random number of places(wrapping around if necessary) and write the shifted and unshifted texts next to each other...  1, fiche 1, Anglais, - index%20of%20coincidence

Fiche 1,  Justifications,  Français

Fiche 1,  Justifications,  Espagnol

Fiche 2,  Justifications,  Anglais

Record number: 2, Textual support number: 1 OBS

Most modern substitution ciphers are of the "double-substitution" type, in which a different cipher alphabet is used to encipher each successive letter of the clear text.  1, fiche 2, Anglais, - double%2Dkey%20substitution

Fiche 2,  Justifications,  Français

Record number: 2, Textual support number: 1 DEF

substitution dans laquelle chaque lettre (unité de chiffrement) est chiffrée à l'aide de deux clefs : une clef simple de substitution (clef de rang); une clef déterminant l'ordre d'emploi de cette clef simple de substitution (clef principale).  1, fiche 2, Français, - substitution%20%C3%A0%20double%20clef

Fiche 2,  Justifications,  Espagnol

Fiche 3,  Justifications,  Anglais

Record number: 3, Textual support number: 1 DEF

A system of polyalphabetic substitution equivalent to Vigenère cipher with a reversed normal cipher sequence, the keying formula of which is P + C=K.  1, fiche 3, Anglais, - Beaufort%20cipher

Fiche 3,  Justifications,  Français

Fiche 3,  Justifications,  Espagnol