41 lines
1.2 KiB
Python
41 lines
1.2 KiB
Python
class VigenereCipher(object):
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def __init__(self, key, alphabet):
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self.key = key
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self.alphabet = alphabet
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def encode(self, text):
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encoded = []
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idx_key = 0
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for char in text:
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if char in self.alphabet:
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text_pos = self.alphabet.index(char)
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key_char = self.key[idx_key % len(self.key)]
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key_pos = self.alphabet.index(key_char)
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pos = (text_pos + key_pos) % len(self.alphabet)
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encoded.append(self.alphabet[pos])
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else:
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encoded.append(char)
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idx_key += 1
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return "".join(encoded)
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def decode(self, text):
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decoded = []
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idx_key = 0
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for char in text:
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if char in self.alphabet:
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text_pos = self.alphabet.index(char)
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key_char = self.key[idx_key % len(self.key)]
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key_pos = self.alphabet.index(key_char)
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pos = (text_pos - key_pos) % len(self.alphabet)
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decoded.append(self.alphabet[pos])
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else:
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decoded.append(char)
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idx_key += 1
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return "".join(decoded)
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