I'm all for right-out-of-college HN readers disrupting schlerotic industries that actually matter rather than making photosharing apps, but careful, enterprise sales looks like enterprise sales for a reason. The reason is typically because enterprise sales is the key to enterprise purchasing departments' lock. You'd like to think that technological superiority and sincerity will let you steal Cheesy McClueless's ten quarterly sales, but sadly, product quality does not necessarily win out.
You don't have to sell to only large companies. I'm sure a lot of smaller companies would appreciate a security product that could grow with them.
And are the odds of success at trying to sell products to businesses any less than trying to create the next Instagram? Seems like a lot of people are focused on the latter. If you're going to do something risky, go for broke. :-)