Bruce Scheier “Applied cryptography”: In a simple transpositional cipher,the plaintext is written horizontally onto a piece of graph paper of fixed width and the ciphertext is read off vertically. Decryption is a matter of writing the ciphertext vertically onto a piece of graph paper of identical width and then reading the plaintext off horizontally.
Text to be encrypted saved in a file “secret_text.txt”, the width of the transposition matrix saved in a separate file “key.txt”. When program starts, encrypted text is shown to user with the opportunity to guess the key value which is the width of the transposition matrix in certain limits. After providing width value, the program shows the result of decryption with provided key. User may terminate the program after obtaining satisfactory result.
File to be executed in Python