45 lines
1.1 KiB
Python
45 lines
1.1 KiB
Python
import argparse
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def caesar(ptextletter, keyletter):
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ptextNum = ord(ptextletter) - ord('A')
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keyletterNum = ord(keyletter) - ord('A')
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return chr((ptextNum + keyletterNum) % 26 + ord('A'))
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def caesar_reverse(ptextletter, keyletter):
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ptextNum = ord(ptextletter) - ord('A')
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keyletterNum = ord(keyletter) - ord('A')
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return chr((ptextNum - keyletterNum) % 26 + ord('A'))
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def encryption(plaintext, key):
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ciphertext = ''
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for i in range(len(plaintext)):
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ciphertext += caesar(plaintext[i], key[i % len(key)])
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return ciphertext
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def decryption(ciphertext, key):
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plaintext = ''
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for i in range(len(ciphertext)):
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plaintext += caesar_reverse(ciphertext[i], key[i % len(key)])
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return plaintext
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def main():
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# parse command line argument
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parser = argparse.ArgumentParser()
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parser.add_argument('--text', type=str)
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parser.add_argument('--key', type=str)
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args = parser.parse_args()
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key = args.key
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user_text = args.text
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print("Encrypted ciphertext: " + encryption(user_text, key))
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print("Decrypted plaintext: " + decryption(user_text, key))
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if __name__ == '__main__':
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main()
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