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:

    Have Johnny fix him a sandwich or something. Any man running for the Senate has to wantsomething. Right, Bud?
    Okay, start the bus then. And drive them over a cliff.
    Jeremy Larner, U.S. screenwriter, and Michael Ritchie. John J. McKay (Melvin Douglas)

    This is the Key of the Kingdom:
    In that Kingdom is a city;
    —Unknown. This Is the Key (l. 1–2)

    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)