108 lines
2.4 KiB
Python
108 lines
2.4 KiB
Python
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#!/usr/bin/env nix-shell
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#!nix-shell -i python -p python3
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# NOTE: the colors are used to keep track of which letters have been
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# already substituted, and which are still unknown.
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def green(s):
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return f"\033[42m{s}\033[0m"
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def red(s):
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return f"\033[41m{s}\033[0m"
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def substitute(cipher_text, substitution_map):
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for letter in cipher_text:
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if letter.lower() in substitution_map:
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if letter.isupper():
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x = substitution_map[letter.lower()].upper()
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else:
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x = substitution_map[letter]
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print(green(x), end="")
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else:
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print(red(letter), end="")
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with open('message.txt', 'r') as file:
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enc = file.read()
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# Here, I will be slowly substituting the letters in the ciphertext
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# based on what I believe the words to be. I have commented out the
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# invocations of substitute, and commented the newly found letters
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# after each invocation.
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# Starting off, "pvncDCM{...}" looks like "picoCTF{...}"
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substitution_map = {
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'0': '0',
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'1': '1',
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'2': '2',
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'3': '3',
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'4': '4',
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'5': '5',
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'6': '6',
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'7': '7',
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'8': '8',
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'9': '9',
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'-': '-',
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'_': '_',
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'\n': '\n',
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' ': ' ',
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',': ',',
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'.': '.',
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':': ':',
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';': ';',
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'{': '{',
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'}': '}',
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'p': 'p',
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'v': 'i',
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'n': 'c',
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'c': 'o',
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'd': 't',
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'm': 'f',
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}
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# substitute(enc, substitution_map)
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# 'Dsu fxow ij' -> 'The flag is'
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substitution_map['d'] = 't'
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substitution_map['s'] = 'h'
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substitution_map['u'] = 'e'
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substitution_map['x'] = 'l'
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substitution_map['o'] = 'a'
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substitution_map['w'] = 'g'
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substitution_map['j'] = 's'
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# substitute(enc, substitution_map)
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# 'taligg all thiggs igto cogsifeaatiog' -> 'taking all things into consideration'
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# 'rhich' -> 'which'
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substitution_map['l'] = 'k'
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substitution_map['g'] = 'n'
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substitution_map['f'] = 'd'
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substitution_map['a'] = 'r'
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substitution_map['r'] = 'w'
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# substitute(enc, substitution_map)
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# 'roynd hlack spots' -> 'round black spots'
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# 'ekceedinglq' -> 'exceedingly'
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substitution_map['y'] = 'u'
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substitution_map['h'] = 'b'
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substitution_map['q'] = 'y'
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substitution_map['k'] = 'x'
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# substitute(enc, substitution_map)
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# 'iery reearkable' -> 'very remarkable'
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# 'pribe' -> 'pride'
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# 'Zupiter' -> 'Jupiter'
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substitution_map['i'] = 'v'
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substitution_map['e'] = 'm'
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substitution_map['b'] = 'd'
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substitution_map['z'] = 'j'
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substitute(enc, substitution_map)
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