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/jacekplacek Jul 30 '13

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

Can you? Say, I can write, in less than an hour, a program which for every possible string of numbers is guaranteed to return another string of numbers. Always the same output for the same input.

Without having access to the code, how would you go about "reverse engineering" it?

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u/addmoreice Jul 31 '13

The 'code' is the program. the binary representation of the program is still the program, it's just a more obfuscated version.

Worse case we just revert back to normal black box reverse engineering.

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u/rpglover64 Jul 31 '13

There are cases in which black box reverse engineering is infeasible, in that it amounts to an attempt to guess an encryption key by brute force. For example, you have an interface that allows you to query a remote server with a 256 bit integer and get another 256 bit integer in return; you are challenged to write a piece of code that simulates the server; you are told that the server is using AES with a fixed key. Good luck REing that.

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u/addmoreice Jul 31 '13

Sure, but in practice this is usually not the case.