Search results
Results From The WOW.Com Content Network
A book cipher is a cipher in which each word or letter in the plaintext of a message is replaced by some code that locates it in another text, the key . A simple version of such a cipher would use a specific book as the key, and would replace each word of the plaintext by a number that gives the position where that word occurs in that book.
One-time pad. A format of one-time pad used by the U.S. National Security Agency, code named DIANA. The table on the right is an aid for converting between plaintext and ciphertext using the characters at left as the key. In cryptography, the one-time pad ( OTP) is an encryption technique that cannot be cracked, but requires the use of a single ...
A disk cipher device of the Jefferson type from the 2nd quarter of the 19th century in the National Cryptologic Museum. The Jefferson disk, also called the Bazeries cylinder or wheel cypher, was a cipher system commonly attributed to Thomas Jefferson that uses a set of wheels or disks, each with letters of the alphabet arranged around their edge in an order, which is different for each disk ...
The Vigenère cipher is named after Blaise de Vigenère (pictured), although Giovan Battista Bellaso had invented it before Vigenère described his autokey cipher. The Vigenère cipher ( French pronunciation: [viʒnɛːʁ]) is a method of encrypting alphabetic text where each letter of the plaintext is encoded with a different Caesar cipher ...
In cryptography, a cipher (or cypher) is an algorithm for performing encryption or decryption —a series of well-defined steps that can be followed as a procedure. An alternative, less common term is encipherment. To encipher or encode is to convert information into cipher or code. In common parlance, "cipher" is synonymous with "code", as ...
In cryptanalysis, frequency analysis (also known as counting letters) is the study of the frequency of letters or groups of letters in a ciphertext. The method is used as an aid to breaking classical ciphers . Frequency analysis is based on the fact that, in any given stretch of written language, certain letters and combinations of letters ...
The pigpen cipher (alternatively referred to as the masonic cipher, Freemason's cipher, Rosicrucian cipher, Napoleon cipher, and tic-tac-toe cipher) [2] [3] is a geometric simple substitution cipher, which exchanges letters for symbols which are fragments of a grid. The example key shows one way the letters can be assigned to the grid.
Polyalphabetic cipher. A polyalphabetic cipher is a substitution, using multiple substitution alphabets. The Vigenère cipher is probably the best-known example of a polyalphabetic cipher, though it is a simplified special case. The Enigma machine is more complex but is still fundamentally a polyalphabetic substitution cipher.