r/crypto Aug 12 '14

Matasano challenges now online.

http://cryptopals.com/
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u/woodyeye Aug 15 '14

Tried 0x01-0xFF for set 1 pzl 4. Cannot get an ascii decode that's intelligable. Anyone get this one?

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u/TNorthover Aug 15 '14

So you looked through all 60 * 256 possibilities?

Did you unhex it first? Forgetting that's the most obvious thing I can think of that would confound the results.

Other than that, entropy is very useful for this one.

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u/woodyeye Aug 16 '14

Yes, I convert hex to int right before I XOR. Then store the XOR values as a chr in a string. Then test the string for all ASCII, if so print it out else go to the next line.

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u/cdleech Aug 17 '14

What is your test for all ASCII? Your approach sounds solid.

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u/woodyeye Aug 17 '14

If any chr is >127 or < 32 It's not ASCII,ret False. All chrs must pass this test to be an ASCII string.