I was having a chat with a coworker who is working on a polling app and framework. He was asking technical questions and I suggested he open source the application to get more quality opinions from developers who are interested in this problem and are willing to give it heavy though. He has a different point of view which I think is still valid so I want to open this question for discussion here. He says he believes something like a polling framework should not be open sourced because it will reduce its security and validity as people reveal loopholes through which they can cheat. Can't say I completely disagree. I see a somewhat valid point there, but I always believed that solutions by a group of people are almost always better than a solution thought by a single person asking a small number of coworkers, no matter how smart that person is. Again I'm willing to accept that maybe some types of applications are different. Does anyone have an argument in his favor? I'd really like to present your responses to him. 
Should a poll framework be closed sourced
web development;php;open source
You're talking about polls on websites, I'm assuming? The which is your favourite language, C#, Java or COBOL? type polls? If so, that's an interesting one.Normally I would agree with Simon's answer that if opening the source reveals loopholes, it was never secure to begin with.However, for this sort of app.. the chances are that no, it wasn't secure to begin with, and can't easily be made so. Problem is, I'm betting that you have a requirement for people to be able to just come to the website and vote in the poll, no registration required. And you also have the incompatible requirement that people should only be able to vote once.So whatever you do.. there's a loophole. Checking IP addresses? Visitor who wants to cheat knows to use a proxy. Cookies? Visitor who wants to cheat knows to clear his cookies. Opening the source makes it trivial to see how to cheat.But having said that.. it's trivial anyway. Doesn't take very long to try the alternatives and see which one allows multiple votes. It's just not possible to make this sort of anonymous poll secure, so you might as well open source it and at least get eyeballs spotting bugs!