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. Columnar Transposition 

. Columnar Transposition . 1 . Compute the characters in plaintext.

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. Columnar Transposition 

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  1. . Columnar Transposition  1. Compute the characters in plaintext. 2. Create two dimensional matrix (no. of row × no. of columns equal the length of plaintext and be sure that the no. of columns must be the largest, for example, if the length of plaintext equal to 15 then the Dim of a matrix will be 3×5 ( 3-rows and 5-columns). If the length of plaintext equal to 17 then the Dim of a matrix will be 3×6 (3-rows and 6-columns).

  2. . Columnar Transposition  3. The length of key equal to the no. of columns. 4. Fill matrix locations with characters of plaintext row by row and in case there is an empty location in matrix, fill it with (x). 5. Put the key as a label for columns. 6. To get the cipher text, scan the columns of matrix depending on key values and take the corresponding matrix values.

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  7. Columnar Transposition Ex :Encrypt the message (P= WE ARE DISCOVERED FLEE AT ONCE ) , the Key = ZEBRAS Plaintext = WE ARE DISCOVERED FLEE AT ONCE Key = ZEBRAS SORT KEY = ABERSZ =123456 New key = 632415

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  10. Simple Transposition (Fixed Period d) 1. Divide plaintext into equal periods. 2. The length of key equal to the length of period, if d=4 then length of key =4.

  11. Simple Transposition (Fixed Period d)encryption Example :                   Plain text: CRYPTOGRAPHY , d=4 , key =2 4 1 3 (Encipherment process)                         d=4      d=4      d=4                         CRYP   TOGR   APHY                        1 2 3 4      1 2 3 4     1 2 3 4   Cipher text: RPCY ORTG  PYAH 

  12. Simple Transposition (Fixed Period d)Decryption Decipherment process)  d=4,  key = 2413 Cipher text: 2 4 1  3  2 4 1 3  2 4 1 3  R P C Y O R T GP Y A H Plaintext :CRYP   TOGR  APHY 

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