Caesar Cipher

Caesar Cipher Encryption-to-Decryption (Python)

#Caesar Cipher Python Part 1 of 2 - Encryption

#dictionary
text_id = {"a":0, "b":1, "c":2, "d":3, "e":4, "f":5, "g":6, "h":7, "i":8, "j":9, "k":10, "l":11, "m":12, "n":13, "o":14, "p":15, "q":16, "r":17, "s":18, "t":19, "u":20, "v":21, "w":22, "x":23, "y":24, "z":25}
id_text = {0:"a", 1:"b", 2:"c", 3:"d", 4:"e", 5:"f", 6:"g", 7:"h", 8:"i", 9:"j", 10:"k", 11:"l", 12:"m", 13:"n", 14:"o", 15:"p", 16:"q", 17:"r", 18:"s", 19:"t", 20:"u", 21:"v", 22:"w", 23:"x", 24:"y", 25:"z"}

#shift by a number
n=1

#input
raw_message = input("please enter one word. HINT: Do not use hyphens, special characters, spaces, or numbers.")
print(raw_message)

#convert imput to encrypted text                i.e. Cat 
for character in raw_message:
   print(character)
   converted_number = text_id[character]        #converted num line
   shifted_number = converted_number + n        #mapping letters to numbers
   print(shifted_number)
   if (shifted_number>25):                      #this is the if statement so we don't go over the 26 number of characters in the alphabet
      shifted_number = shifted_number -26       
   print(shifted_number)
   print(id_text[shifted_number])               #this line prints the letter associated with the "shifted_number"
   

#Caesar Cipher Python Part 2 of 2 - Decryption
  
   
   #dictionary
text_id = {"a":0, "b":1, "c":2, "d":3, "e":4, "f":5, "g":6, "h":7, "i":8, "j":9, "k":10, "l":11, "m":12, "n":13, "o":14, "p":15, "q":16, "r":17, "s":18, "t":19, "u":20, "v":21, "w":22, "x":23, "y":24, "z":25}
id_text = {0:"a", 1:"b", 2:"c", 3:"d", 4:"e", 5:"f", 6:"g", 7:"h", 8:"i", 9:"j", 10:"k", 11:"l", 12:"m", 13:"n", 14:"o", 15:"p", 16:"q", 17:"r", 18:"s", 19:"t", 20:"u", 21:"v", 22:"w", 23:"x", 24:"y", 25:"z"}

#input
raw_message = "lbu"                            #manual

#shift by a number
n=1

print(raw_message)

#step 6. decrypt the message
for character in raw_message:
   print("------------------")
   print(character)
   converted_number = text_id[character]     #converted num line
   print(converted_number)
   shifted_number = converted_number - n     #mapping letters to numbers
   print(shifted_number)
   if (shifted_number<0):                    #this is the if statement so we don't go over the 26 number of characters in the alphabet
      shifted_number = shifted_number + 26   #this is the converse of the code above where we subtracted 26   
   print(shifted_number)
   print("------------------")
   print(id_text[shifted_number])            #this line prints the letter associated with the "shifted_number"
   #turn decrypted text into one string
   

print("------------------")  

Further Reading. - Cryptography
https://pymotw.com/3/hmac/index.html
https://pymotw.com/3/hashlib/index.html