34 lines
829 B
Markdown
34 lines
829 B
Markdown
Question: Easy1
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Key: picoCTF{CRYPTOISFUN}
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Core concept: Vignere Cypher - Decrypted character=(Encrypted character−Key character+26)mod26
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Can be solved by an easy Python script:
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```py
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def decrypt_vigenere(encrypted_text, key):
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decrypted_text = ""
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key_length = len(key)
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for i in range(len(encrypted_text)):
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encrypted_char_pos = ord(encrypted_text[i]) - ord('A')
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key_char_pos = ord(key[i % key_length]) - ord('A')
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decrypted_char_pos = (encrypted_char_pos - key_char_pos + 26) % 26
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decrypted_char = chr(decrypted_char_pos + ord('A'))
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decrypted_text += decrypted_char
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return decrypted_text
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encrypted_flag = "UFJKXQZQUNB"
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key = "SOLVECRYPTO"
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decrypted_flag = decrypt_vigenere(encrypted_flag, key)
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print("Decrypted Flag:", decrypted_flag)
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```
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Output: CRYPTOISFUN
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