One of the effects of User Account Control on Windows Vista is that whenever you run a software installer you are asked to confirm if you really want to run it and if you agree, you are either elevated to the mighty powers of an Administrator or you’re asked to enter the credentials of one. The idea behind this is to make sure that you don’t accidentally install something dodgy or some evil software doesn’t manage to install itself without you knowing about it.
It can be quite annoying although it is a useful measure against spyware and malware. However, when launching my installer for John’s Background Switcher I would get this rather scary dialog:
Windows Vista cares a lot more about digital signatures than previous versions of Windows. To obtain a digital certificate to sign your software you have to go through an authorisation process to verifiably identify your company or yourself. If you’re a malware author you’re not likely to get a digital certificate because it costs money, you’d have to identify yourself to an issuing authority and as soon as you’re reported for making malware your certificate would be revoked. So if the installer you run is digitally signed with a valid certificate Windows Vista can be pretty sure it’s not likely to be evil software that’ll take over your computer. In this case it presents a much prettier dialog that’s far less likely to scare any normal user into cancelling. And there’s no orange in sight.
For this reason (and because I thought it would be cool) I decided to stump up a bit of cash and buy my own digital certificate in my name (since I don’t have my own company). After sending a copy of my passport to the issuing authority I can now sign any software I create so that it’s uniquely identified as coming from me. So now when you run my installer you’re shown this:
It’s a far friendlier dialog and I hope that people being presented with it are much less suspicious that my software has some evil, ulterior motive. Also, if someone tampers with my installer, the signature will become invalid and Windows will complain.
It’s a bit of a pain having to pay for a digital certificate to stop Windows from scaring off potential users but I guess that’s thanks to all those dodgy malware authors out there exploiting the formerly trusting nature of Windows. Grrrr.