Running Key Cipher

In classical cryptography, the running key cipher is a type of polyalphabetic substitution cipher in which a text, typically from a book, is used to provide a very long keystream. Usually, the book to be used would be agreed ahead of time, while the passage to use would be chosen randomly for each message and secretly indicated somewhere in the message.

Read more about Running Key Cipher:  Example, Variants, Security, Confusion

Famous quotes containing the words running, key and/or cipher:

    “It’s not like I was out there running and not knowing what’s going on in the country. I knew what was going on, but I felt this is not something that is going to bog me down and not let me participate. The only way I was going to make a difference for myself or any other black person is to say the hurdles were there and do what I had to do.”
    —Wyomia Tyus (b. 1945)

    “I cannot tell what I am as much afraid of, as a woman who invariably washes on Monday. It is a kind of key to character; and if her mouth is not puckered and her brow wrinkled, they will be, unless she repents.”
    —Jane Grey Swisshelm (1815–1884)

    “The eye is the first circle; the horizon which it forms is the second; and throughout nature this primary figure is repeated without end. It is the highest emblem in the cipher of the world.”
    —Ralph Waldo Emerson (1803–1882)