71 lines
2.6 KiB
Python
71 lines
2.6 KiB
Python
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#!/usr/bin/env python3
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import argparse
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import string
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parser: argparse.ArgumentParser = argparse.ArgumentParser(
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prog='Basic Vigenère Cypher',
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description='A quick and dirty implementation of the Vigenére Cypher. Accepts any key as the key.',
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epilog='Enter the message first and the key second.'
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)
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group = parser.add_mutually_exclusive_group(required=True)
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group.add_argument('-e', '--encrypt', nargs=2, help="Message to be decrypted or encrypted and the key used")
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group.add_argument('-d', '--decrypt', nargs=2, help="Message to be decrypted or encrypted and the key used")
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class Vigenere:
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def __init__(self) -> None:
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self.args = parser.parse_args()
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self.chars: str = ''.join(c for c in string.printable if c.isprintable()) + ''.join(chr(c) for c in range(128, 256) if not chr(c).isspace or c in (160,)) # All Characters from extended ASCII, excluding control codes
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if self.args.encrypt:
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self.msg: str = self.args.encrypt[0]
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self.key: str = self._generate_key(self.args.encrypt[1])
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else:
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self.msg: str = self.args.decrypt[0]
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self.key: str = self._generate_key(self.args.decrypt[1])
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def _generate_key(self, key: str) -> str:
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if len(key) < len(self.msg):
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key = (key * (len(self.msg) // len(key) + 1))[:len(self.msg)]
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else:
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key = key[:len(self.msg)]
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return key
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def _create_alphabet(self, shift: int) -> str:
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alphabet: str = self.chars
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shift = (shift % len(alphabet))
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return alphabet[shift:] + alphabet[:shift]
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def _find_index(self, index: int) -> int:
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return self.chars.index(self.key[index])
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def encrypt(self) -> str:
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encrypted_msg: str = ""
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for index in range(len(self.msg)):
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char: str = self.msg[index]
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lookup_alphabet: str = self._create_alphabet(self._find_index(index))
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original_index: int = self.chars.index(char)
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encrypted_msg += lookup_alphabet[original_index]
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return encrypted_msg
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def decrypt(self) -> str:
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decrypted_msg: str = ""
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for index in range(len(self.msg)):
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lookup_alphabet: str = self._create_alphabet(self._find_index(index))
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location_index: int = lookup_alphabet.index(self.msg[index])
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decrypted_msg += self.chars[location_index]
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return decrypted_msg
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def output(self) -> None:
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if self.args.encrypt:
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ciphertext = self.encrypt()
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print(ciphertext)
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else:
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plaintext = self.decrypt()
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print(plaintext)
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if __name__ == "__main__":
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vigenere_cipher = Vigenere()
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vigenere_cipher.output()
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