The Bitcoin.org client is open source.   That means the source code in the Bitcoin-Qt client that you run is visible to anyone and everyone.  There are "super hackers" looking at this code as well.  And at other clients as well, BitcoinJ, etc.  There's $300+ million worth of bitcoin funds there for the taking to the first person to figure out some exploit (actually, that's not true ... if there were an exploit the value would plummet, or else a fix is made and losses were only incurred by those who exchanged value for certain bitcoins that ultimately were made worthless due to the fix of the exploit.)


There's a saying that "no one of us is smarter than all of us".  There may be a super hacker smarter out there smarter than the most skilled person working on Bitcoin.  But there isn't a super hacker that is smarter than all the people working on bitcoin collectively.
 - http://en.wikipedia.org/wiki/Distributed_knowledge