I'm Brazilian and this media statement is full os shit, why ?
1st - To try to hack it you had to submit a paper telling EVERYTHING you would try to hack... Any hacker knows that "hacking" isn't easy, and you must adjust your techniques every time, so it is virtually impossible to design a paper telling what you're going to do. Hacking isn't simply mathematics and scheduled procedures...
2nd - They would allow you very limited access to the voting machine in a controlled everinoment and on a limited time. Hacking takes days to understand the code, flaws ans possible ways to exploit it. It can't be done under pressure in a few days.
3rd - No REAL hacker would show his personal information and submit it to the goverment. Why ? It's very clear that everyone who enlisted was added to a federal police database of "possible suspects" and only the winner (almost impossible to archive, due the circunstances) would gain anything. So the chance of winning was very low, and being exposed wasn't worth the try.
If they want a REAL test, they must:
1 - Allow anyone read the full source-code
2 - Put some of those voting machines on the internet with full-access. (login and passwords)
3 - Let us try anything without pressure.
4 - Offer a REAL prize, like US$100.000.
5 - Get a chance to try to hack it without being exposed in the first-hand. Of course whoever wins must reveal his identity, but only the winner (and everything that would come from that) would be known.
That said, it was just a media statement... I can BET there are a lot of flaws in the system...