86 lines
2.0 KiB
Python
86 lines
2.0 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 in substitution_map:
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print(green(substitution_map[letter]), end="")
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else:
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print(red(letter), end="")
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with open('ciphertext', '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, "csds bh reod kzim" looks like "here is your flag"
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substitution_map = {
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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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'c': 'h',
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's': 'e',
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'd': 'r',
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'b': 'i',
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'h': 's',
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'r': 'y',
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'e': 'o',
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'o': 'u',
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'k': 'f',
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'z': 'l',
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'i': 'a',
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'm': 'g',
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}
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# substitute(enc, substitution_map)
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# found: euro't'e, ligh'a', o'f'er, 'q'ri'a'ish
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# suspect: euro p e, ligh t, o v er, b ri t ish
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substitution_map['t'] = 'p'
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substitution_map['a'] = 't'
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substitution_map['f'] = 'v'
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substitution_map['q'] = 'b'
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# substitute(enc, substitution_map)
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# found: visite'n', british 'y'useu'y', sear'p'h, havi'x'g
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# suspect: visite d , british m useu m , sear c h, havi'n'g
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substitution_map['n'] = 'd'
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substitution_map['y'] = 'm'
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substitution_map['p'] = 'c'
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substitution_map['x'] = 'n'
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# substitute(enc, substitution_map)
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# found: fre'g'uency, 'l'no'w'n, 'j'ust, e'v'act
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# suspect: fre q uency, k no w n, j ust, e'x'act
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substitution_map['g'] = 'q'
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substitution_map['l'] = 'k'
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substitution_map['w'] = 'w'
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substitution_map['j'] = 'j'
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substitution_map['v'] = 'x'
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substitute(enc, substitution_map)
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# still not sure about 'u'? But flag is found
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