85 lines
2.3 KiB
Python
85 lines
2.3 KiB
Python
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from utils import AlphabetUtils as au
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def encrypt_text(cleartext: str, keyword: str) -> str:
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"""
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Encrypts the given text with the given keyword
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:param cleartext: The text to encrypt
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:param keyword: The keyword to use
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:return: The encrypted text
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"""
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# If the ciphertext is longer than the keyword, we need to multiply the keyword
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while len(cleartext) > len(keyword):
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keyword += keyword
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resulting = ''
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for char_index in range(len(cleartext)):
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char = cleartext[char_index]
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key = keyword[char_index]
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cipherchar = _get_corresponding_cipher(char, key)
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resulting += cipherchar
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return resulting
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def decrypt_text(ciphertext: str, keyword: str) -> str:
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"""
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Decrypts the given ciphertext with the given keyword
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:param ciphertext: The text to decrypt
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:param keyword: The keyword to use
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:return: The decrypted text
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"""
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# If the ciphertext is longer than the keyword, we need to multiply the keyword
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while len(ciphertext) > len(keyword):
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keyword += keyword
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resulting = ''
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for char_index in range(len(ciphertext)):
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char = ciphertext[char_index]
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key = keyword[char_index]
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clearchar = _get_corresponding_char(char, key)
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resulting += clearchar
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return resulting
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def _get_corresponding_cipher(char: str, key: str) -> str:
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"""
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Calculates the corresponding cipher char for the given clearchar/keychar combination using the vigenere square
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:param char: The cleartext char
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:param key: The keyword char
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:return: The cipher char
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"""
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char_index = au.get_index_of_letter(char)
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key_index = au.get_index_of_letter(key)
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# Based on the layout of the vigenere square, this should in theory work
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cipher_index = (char_index + key_index) % 26
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return au.get_letter_at_index(cipher_index)
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def _get_corresponding_char(cipher: str, key: str) -> str:
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"""
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Calculates the corresponding cleartext char for the given cipherchar/keychar combination using the vigenere square
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:param cipher: The cipher char
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:param key: The keyword char
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:return: The cleartext char
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"""
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cipher_index = au.get_index_of_letter(cipher)
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key_index = au.get_index_of_letter(key)
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# Based on the layout of the vigenere square, this should in theory work
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char_index = (cipher_index - key_index) % 26
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return au.get_letter_at_index(char_index)
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if __name__ == '__main__':
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print(encrypt_text('BonkRocks', 'SuperSecretKeyword'))
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print(decrypt_text('ticoiggmj', 'SuperSecretKeyword'))
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