Just because you don't have the source code does not mean you cannot inspect what a binary does by disassembling it. (And as any programmer will tell you, just

Just because you don't have the source code does not mean you cannot inspect what a binary does by disassembling it. (And as any programmer will tell you, just because you have the source code available does not automatically mean you can see where it has a tricky edge case with massive security implications. The obfuscated C contests are proof of that)