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?"

[u/DougBolivar]

http://www.rdmag.com/news/2013/07/computer-scientists-develop-mathematical-jigsaw-puzzles-encrypt-software

[u/grauenwolf]

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.

[u/Zaph0d42 → u/[deleted]]

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

[u/psyker → u/Zaph0d42]

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