[userbinator]

I remember a very similar technique being used successfully for automatically cracking software (registration keys/keyfiles, serial numbers) before Internet-based validation and stronger crypto became common; the difference is that method didn't require having access to any source code or recompiling the target, as it just traced execution and "evolved" itself toward inputs producing longer and wider (i.e. more locations in the binary) traces.

[joshschreuder]

That sounds interesting, do you have any more information on this topic?