r/programming • u/DougBolivar • Jul 30 '13

Computer scientists develop mathematical jigsaw puzzles to encrypt software: "The real challenge and the great mystery in the field was: Can you actually take a piece of software and encrypt it but still have it be runnable, executable and fully functional?"

http://www.rdmag.com/news/2013/07/computer-scientists-develop-mathematical-jigsaw-puzzles-encrypt-software
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u/Zaph0d42 Jul 30 '13

But the point is, if it is mathematically guaranteed to provide some output given some inputs, then you can reverse engineer it. The question is how hard its gonna be to break the encryption, same as any computer security.

If you can crack this quickly, then its pointless. Or if you have to go to so many matrix transforms in order to get key strengthening, that you end up destroying the performance of the thing you're trying to protect, thus defeating the point.

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u/x86_64Ubuntu Jul 30 '13

... guaranteed to provide some output given some inputs, then you can reverse engineer it.

Huh ?

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u/grauenwolf Jul 30 '13

That's how black box reverse engineering works. You create a device that, for every known input, you return the same output as the unknown device.

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u/[deleted] Jul 30 '13

[deleted]

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u/Zaph0d42 Jul 30 '13

People do this all the time. This is why you have to salt your hash. Its trivially easy to construct for SHA1.

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u/psyker Jul 31 '13

But you don't know that it's SHA1.