In Python 3 please explain with comments when possible. In cryptography, a Caesa

Question

In Python 3 please explain with comments when possible.

In cryptography, a Caesar cipher is a very simple encryption technique in which each letter in the plain text is replaced by a letter some fixed number of positions down the alphabet. For example, with a shift of 3, A would be replaced by D, B would become E, and so on. The method is named after Julius Caesar, who used it to communicate with his generals. ROT-13 ("rotate by 13 places") is a widely used example of a Caesar cipher where the shift is 13. In Python, the key for ROT-13 may be represented by means of the following dictionary:

• implement an encoder/decoder of ROT-13. Once you're done, you will be able to read the following secret message:

•Pnrfne pvcure? V zhpu cersre Pnrfne fnynq!

{C}

•In your answer, make sure to deal with non-alpha characters (punctuation, numbers, etc.)

{C}

crypto_dict = {'a':'n', 'b':'o', 'c':'p', 'd':'q', 'e':'r', 'f':'s', 'g':'t', 'h':'u',

       'i':'v', 'j':'w', 'k':'x', 'l':'y', 'm':'z', 'n':'a', 'o':'b', 'p':'c',

       'q':'d', 'r':'e', 's':'f', 't':'g', 'u':'h', 'v':'i', 'w':'j', 'x':'k',

       'y':'l', 'z':'m', 'A':'N', 'B':'O', 'C':'P', 'D':'Q', 'E':'R', 'F':'S',

       'G':'T', 'H':'U', 'I':'V', 'J':'W', 'K':'X', 'L':'Y', 'M':'Z', 'N':'A',

       'O':'B', 'P':'C', 'Q':'D', 'R':'E', 'S':'F', 'T':'G', 'U':'H', 'V':'I',

       'W':'J', 'X':'K', 'Y':'L', 'Z':'M'}

Explanation / Answer

crypto_dict = {'a':'n', 'b':'o', 'c':'p', 'd':'q', 'e':'r', 'f':'s', 'g':'t', 'h':'u',
'i':'v', 'j':'w', 'k':'x', 'l':'y', 'm':'z', 'n':'a', 'o':'b', 'p':'c',
'q':'d', 'r':'e', 's':'f', 't':'g', 'u':'h', 'v':'i', 'w':'j', 'x':'k',
'y':'l', 'z':'m', 'A':'N', 'B':'O', 'C':'P', 'D':'Q', 'E':'R', 'F':'S',
'G':'T', 'H':'U', 'I':'V', 'J':'W', 'K':'X', 'L':'Y', 'M':'Z', 'N':'A',
'O':'B', 'P':'C', 'Q':'D', 'R':'E', 'S':'F', 'T':'G', 'U':'H', 'V':'I',
'W':'J', 'X':'K', 'Y':'L', 'Z':'M'}

def encoder(message):
encryptedMsg = ""
for x in message:
if x.isalpha():
encryptedMsg += crypto_dict[x]
else:
encryptedMsg += x
return encryptedMsg

def decoder(message):
decryptedMsg = ""
for x in message:
if x.isalpha():
decryptedMsg += crypto_dict[x]
else:
decryptedMsg += x
return decryptedMsg
  
print(decoder("Pnrfne pvcure? V zhpu cersre Pnrfne fnynq!"))

# If indentation is messed up please see code here: https://paste.ee/p/Rv8Dh

Encrypted message is:

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