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:
““Would you—be good enough—” Alice panted out, after running a little further, “to stop a minute—just to get—one’s breath again?”
“I’m good enough,” the King said, “only I’m not strong enough. You see, a minute goes by so fearfully quick. You might as well try to stop a Bandersnatch!””
—Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)
“The safety of the republic being the supreme law, and Texas having offered us the key to the safety of our country from all foreign intrigues and diplomacy, I say accept the key ... and bolt the door at once.”
—Andrew Jackson (1767–1845)
“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)