Search results
Results from the WOW.Com Content Network
The Rail Fence cipher is a form of transposition cipher that gets its name from the way in which it is encoded. In the rail fence cipher, the plaintext is written downward and diagonally on successive "rails" of an imaginary fence, then moves up when it gets to the bottom. The message is then read off in rows.
The cipher's key is , the number of rails. If N {\displaystyle N} is known, the ciphertext can be decrypted by using the above algorithm. Values of N {\displaystyle N} equal to or greater than L {\displaystyle L} , the length of the ciphertext, are not usable, since then the ciphertext is the same as the plaintext.
Although ciphers can be confusion-only (substitution cipher, one-time pad) or diffusion-only (transposition cipher), any "reasonable" block cipher uses both confusion and diffusion. [2] These concepts are also important in the design of cryptographic hash functions , and pseudorandom number generators , where decorrelation of the generated ...
The first letter of each ciphertext pair is the row, and the second ciphertext letter is the column, of the plaintext letter in the grid (e.g., "AF" means "row A, column F, in the grid"). Next, the fractionated message is subject to a columnar transposition. The message is written in rows under a transposition key (here "CARGO"):
The sender chooses a set number of words at random from the poem and gives each letter in the chosen words a number. The numbers are then used as a key for a transposition cipher to conceal the plaintext of the message. The cipher used was often double transposition. To indicate to the receiver which words had been chosen, an indicator group of ...
Facsimile of a BATCO cipher sheet. BATCO , short for Battle Code, is a hand-held, paper-based encryption system used at a low, front line (platoon, troop and section) level in the British Army . It was introduced along with the Clansman combat net radio in the early 1980s and was largely obsolete by 2010 due to the wide deployment of the secure ...
The transposition described is a write-by-row, read-by-column route transposition, not a route transposition, as that term is used in, for example, Helen Gaines 1939 "Elementary Cryptanalysis." Somewhere along the line someone on the web posted an incorrect description, and it's been passed along from site-to-site since.
All polyalphabetic ciphers based on the Caesar cipher can be described in terms of the tabula recta. The tabula recta uses a letter square with the 26 letters of the alphabet followed by 26 rows of additional letters, each shifted once to the left from the one above it. This, in essence, creates 26 different Caesar ciphers. [1]