Chapter 8 – The Transposition Cipher, Encrypting 99

12. 
    

    Print the encrypted string in ciphertext to the screen, with

    
    


13. 
    

    a | (called "pipe" character) after it in case there are spaces at

    
    


14. 
    

    the end of the encrypted message.

    
    


15. print(ciphertext + '|')


16. 
    


17. 
    

    Copy the encrypted string in ciphertext to the clipboard.

    
    


18. pyperclip.copy(ciphertext)


19. 
    


20. 
    


21. def encryptMessage(key, message):


22. 
    

    Each string in ciphertext represents a column in the grid.

    
    


23. ciphertext = [''] * key


24. 
    


25. 
    

    Loop through each column in ciphertext.

    
    


26. for col in range(key):


27. pointer = col


28. 
    


29. 
    

    Keep looping until pointer goes past the length of the message.

    
    


30. while pointer < len(message):


31. 
    

    Place the character at pointer in message at the end of the

    
    


32. 
    

    current column in the ciphertext list.

    
    


33. ciphertext[col] += message[pointer]


34. 
    


35. 
    

    move pointer over

    
    


36. pointer += key


37. 
    


38. 
    

    Convert the ciphertext list into a single string value and return it.

    
    


39. return ''.join(ciphertext)


40. 
    


41. 
    


42. 
    

    If transpositionEncrypt.py is run (instead of imported as a module) call

    
    


43. 
    

    the main() function.

    
    


44. if name == 'main':


45. main()

Sample Run of the Transposition Cipher Encryption Program

When you run the above program, it produces this output:

Cenoonommstmme oo snnio. s s c|

This ciphertext (without the pipe character at the end) is also copied to the clipboard, so you can
paste it into an email to someone. If you want to encrypt a different message or use a different