![]() ![]() Note, each rotation yields a different ciphertext that could be used. The ciphertext is given by each row, in order, in the result. Transposition Cipher : Transposition Cipher rearranges the position of the characters of plain text. The result after the aforementioned possible rotations are shown below. It uses a simple substitution process or sometimes the permutation process where the block of plain text is substituted with arbitrary bit of cipher text. ![]() If the text "attack at seven pm" should be encoded and we have a block size of 5, then the text is assigned to blocks like this: ATTACKATSEVENPM It can be rotated to the left or to the right by 90°, 180° or 270°. The key in a rotation cipher is composed of the block size and the rotation angle. Then, reading across each row produces the ciphertext "SMTPEDOEROSNRO" For example, if 3 "rails" are chosen and the plaintext message is "send more troops", we would first construct the following rails: When the top rail is reached, the message is written downwards again until the whole plaintext is written out. First, the plaintext is written diagonally downwards on successive "rails" of an imaginary fence, then moving up when the bottom rail is reached. The aim is to start building an understanding of encryption and decryption on a. The rail fence cipher is a transposition cipher where the ciphertext is found from the plaintext in the following way. This activity will introduce you to a selection of transposition ciphers. Since the strip of parchment hints strongly at the method, to increase security the ciphertext should be transferred to something less suggestive, although this of course reduces the advantages previously mentioned. This method of encryption has the advantage of being fast and not prone to mistakes - a necessary property when on the battlefield. The recipient uses a rod of the same diameter on which he wraps the strip of leather or parchment to read the message. The ancient Greeks, and the Spartans in particular, are said to have used this cipher to communicate during military campaigns. The message is then written upon this wound strap, where consecutive letters land on consecutive windings, as shown in the picture above. To encrypt a message with a scytale, one takes a cylinder and winds a strip of parchment or leather around it. The following detail some historically significant transposition ciphers:Ī scytale (which rhymes approximately with "Italy" and from the Greek $\sigma\kappa\upsilon\tau \acute \alpha \lambda\eta$ which means "baton") is a tool that can be used to perform a particular kind of transposition cipher. Transposition CiphersA transposition cipher is a cipher that encrypts a message by scrambling the letters of the original message in some reversible way. ![]()
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