mirror of https://github.com/dirtbags/moth.git
31 lines
1.0 KiB
Python
31 lines
1.0 KiB
Python
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import crypto
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alpha = b'abcdefghiklmnoprstuw'
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alice = b'''The next four puzzles are all transposition cyphers like this one. Transposition, like substition, is still used in modern crypto systems. '''
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bob = b'''Transposition cyphers often work with the text arranged into blocks of a certain width, often as determined by the key. Dangling parts are often padded with nulls or random text. terrifying silence '''
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alice = alice.replace(b' ', b'_').lower()
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bob = bob.replace(b' ', b'_').lower()
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map = [6, 3, 0, 5, 2, 7, 4, 1]
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imap = [2, 7, 4, 1, 6, 3, 0, 5]
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def transform(text, map):
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assert len(text) % 8 == 0, 'Text must be multiple of 8 in length. '\
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'%d more chars needed.' % (8 - len(text) % 8)
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out = bytearray()
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i = 0
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while i < len(text):
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for j in range(8):
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out.append( text[i + map[j]] )
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i = i+8
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return bytes(out)
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encode = lambda t : transform(t, map)
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decode = lambda t : transform(t, imap)
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crypto.mkIndex(encode, decode, alice, bob, crypto.groups)
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