Polyalphabetic Substitution

Some articles on substitution, polyalphabetic substitution, polyalphabetic:

Types of Cipher - Historical Ciphers
... They include simple substitution ciphers and transposition ciphers ... Simple ciphers were replaced by polyalphabetic substitution ciphers which changed the substitution alphabet for every letter ... With even a small amount of known or estimated plaintext, simple polyalphabetic substitution ciphers and letter transposition ciphers designed for pen and paper encryption are easy to crack ...
Substitution Cipher - Polyalphabetic Substitution
... Polyalphabetic substitution ciphers were first described in 1467 by Leone Battista Alberti in the form of disks ... In a polyalphabetic cipher, multiple cipher alphabets are used ... to use next, defines the particular polyalphabetic cipher ...
Japanese Cryptology From The 1500s To Meiji - The Two-Letter, Ten-Chart Code
... This is just a code version of a polyalphabetic substitution cipher ... Polyalphabetic ciphers use several different enciphering alphabets and change between them at some interval, usually after every letter ... The strength of a polyalphabetic cipher comes from how many alphabets it uses to encipher, how often it switches between them, and how it switches between them (at random or following ...

Famous quotes containing the word substitution:

    To play is nothing but the imitative substitution of a pleasurable, superfluous and voluntary action for a serious, necessary, imperative and difficult one. At the cradle of play as well as of artistic activity there stood leisure, tedium entailed by increased spiritual mobility, a horror vacui, the need of letting forms no longer imprisoned move freely, of filling empty time with sequences of notes, empty space with sequences of form.
    Max J. Friedländer (1867–1958)