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45 lines
1.2 KiB
Python
45 lines
1.2 KiB
Python
# The Caesar Cipher Algorithm
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def main():
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message = input("Enter message: ")
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key = int(input("Key [1-26]: "))
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mode = input("Encrypt or Decrypt [e/d]: ")
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if mode.lower().startswith('e'):
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mode = "encrypt"
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elif mode.lower().startswith('d'):
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mode = "decrypt"
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translated = encdec(message, key, mode)
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if mode == "encrypt":
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print("Encryption:", translated)
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elif mode == "decrypt":
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print("Decryption:", translated)
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def encdec(message, key, mode):
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message = message.upper()
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translated = ""
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LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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for symbol in message:
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if symbol in LETTERS:
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num = LETTERS.find(symbol)
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if mode == "encrypt":
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num = num + key
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elif mode == "decrypt":
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num = num - key
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if num >= len(LETTERS):
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num -= len(LETTERS)
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elif num < 0:
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num += len(LETTERS)
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translated += LETTERS[num]
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else:
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translated += symbol
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return translated
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if __name__ == '__main__':
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import doctest
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doctest.testmod()
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main()
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