61 lines
1.0 KiB
Ruby
61 lines
1.0 KiB
Ruby
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#!/usr/bin/ruby
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#
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# Routine for xor encoding a buffer by a 2-byte (intel word) key. The perl
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# version used to pad this buffer out to a 2-byte boundary, but I can't think
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# of a good reason to do that anymore, so this doesn't.
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#
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module Rex
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module Encoding
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module Xor
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class Word < Generic
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def Word.find_key(*crap)
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raise NotImplementedError, "We are lazy bums!", caller
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end
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def Word.keylength
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return 2
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end
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def Word.packspec
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return 'v'
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end
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def Word.pack(num)
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[ num ].pack(packspec)
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end
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def Word.unpack(data)
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data.unpack(packspec)[0]
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end
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def Word.encode(buf, key)
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encoded = ""
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pos = 0
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len = keylength()
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while pos < buf.length
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chunk = buf[pos, len]
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short = len - length(chunk)
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# temporarly pad out if we are short of a word
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chunk .= "\x00" * short
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# add to the result, removing any short padding
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encoded += (pack(unpack(chunk) ^ key))[0, len - short]
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pos += len
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end
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end
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# maybe a bit a smaller of method name?
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def Word.find_key_and_encode()
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end
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end end end end # Word/Xor/Encoding/Rex
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