def EncodeCaesar(message, shift):

shift %= 26

encodedMessage = list(message)

for index, letter in enumerate(message):

if letter.islower():

encodedASCII = ord(encodedMessage[index]) + shift - ord("a")

encodedMessage[index] = chr(encodedASCII % 26 + ord("a"))

elif letter.isupper():

encodedASCII = ord(encodedMessage[index]) + shift - ord("A")

encodedMessage[index] = chr(encodedASCII % 26 + ord("A"))

return "".join(encodedMessage)

def DecodeCaesar(encodedMessage, knownWord):

message = "Not found"

for char in encodedMessage:

if not char.isalpha() and char != " ":

encodedMessage.replace(char, "")

encodedWords = encodedMessage.lower().split()

for i in range(1, 26):

for word in encodedWords:

testWord = EncodeCaesar(word, i)

if knownWord.lower() == testWord:

print("Shift:", 26 - i)

message = EncodeCaesar(encodedMessage, i)

return message

def EncodeVigenere(message, key):

keys = list(key.lower())

encodedMessage = list(message)

offset = 0

for index, letter in enumerate(message):

if letter.islower():

encodedASCII = ord(encodedMessage[index]) - ord("a")

encodedASCIIKey = ord(keys[(index - offset) % len(keys)]) - ord("a")

encodedMessage[index] = chr((encodedASCII + encodedASCIIKey) % 26 + ord("a"))

elif letter.isupper():

encodedASCII = ord(encodedMessage[index]) - ord("A")

encodedASCIIKey = ord(keys[(index - offset) % len(keys)]) - ord("a")

encodedMessage[index] = chr((encodedASCII + encodedASCIIKey) % 26 + ord("A"))

else:

offset += 1

return "".join(encodedMessage)

def DecodeVigenere(message, key):

keys = list(key.lower())

encodedMessage = list(message)

offset = 0

for index, letter in enumerate(message):

if letter.islower():

encodedASCII = ord(encodedMessage[index]) - ord("a")

encodedASCIIKey = ord(keys[(index - offset) % len(keys)]) - ord("a")

encodedMessage[index] = chr((encodedASCII - encodedASCIIKey) % 26 + ord("a"))

elif letter.isupper():

encodedASCII = ord(encodedMessage[index]) - ord("A")

encodedASCIIKey = ord(keys[(index - offset) % len(keys)]) - ord("a")

encodedMessage[index] = chr((encodedASCII - encodedASCIIKey) % 26 + ord("A"))

else:

offset += 1

return "".join(encodedMessage)

action = ""

while action != "q":

action = input("Would you like to quit, encode, or decode? (q, e, d): ")

if action == "e":

cipher = input("What cipher would you like to use? (c for caesar, v for vigenere): ")

message = input("Enter the message you would like to encode: ")

if cipher == "c":

shift = int(input("Enter the shift of the cipher: "))

print("Encoded Message:", EncodeCaesar(message, shift))

elif cipher == "v":

key = input("Enter the key you would like to use: ")

print("Encoded Message:", EncodeVigenere(message, key))

elif action == "d":

cipher = input("What cipher would you like to use? (c for caesar, v for vigenere): ")

encoded_message = input("Enter the encoded message: ")

if cipher == "c":

knownWord = input("Enter a known word: ")

print("Decoded Message:", DecodeCaesar(encoded_message, knownWord))

elif cipher == "v":

key = input("Enter the key of the cipher: ")

print("Decoded Message:", DecodeVigenere(encoded_message, key))