mirror of https://github.com/dirtbags/moth.git
49 lines
1.3 KiB
Python
49 lines
1.3 KiB
Python
#!/usr/bin/python3
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"""This is non-obvious, so let me elaborate. The message is translated to
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binary with one character per binary bit. Lower case characters are 1's,
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and upper case is 0. The letters are chosen at random. Tricky, eh?"""
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import random
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lower = b'abcdefghijklmnopqrstuvwxyz'
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upper = lower.upper()
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plaintext = [b'The next puzzle starts in the same way, but the last step is '
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b'different.',
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b'We wouldn\'t want them to get stuck so early, would we? '
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b'Rat Fink']
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def encode(text):
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out = bytearray()
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mask = 0x80
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for t in text:
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for i in range(8):
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if t & mask:
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out.append(random.choice(lower))
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else:
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out.append(random.choice(upper))
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t = t << 1
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return bytes(out)
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def decode(text):
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out = bytearray()
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i = 0
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while i < len(text):
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c = 0
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mask = 0x80
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for j in range(8):
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if text[i] in lower:
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c = c + mask
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mask = mask >> 1
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i = i + 1
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out.append(c)
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return bytes(out)
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c = encode(plaintext[0])
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print('<dl><dt>Alice<dd>', str(c, 'utf-8'))
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assert decode(c) == plaintext[0]
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c = encode(plaintext[1])
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print('<dt>Bob<dd>', str(c, 'utf-8'), '</dl>')
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assert decode(c) == plaintext[1]
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