Flash CS5: The Missing Manual

Create a Code Signing Certificate

In the previous exercise, you wrote an AIR app that you can test inside Flash, but that's about all it can do. You can't save it in a format that runs outside Flash or share it with your friends. If you want to produce a program that runs as a standalone desktop app and distribute it, you need to give people a way to confirm where it's coming from. In other words, you need to get a code signing certificate. After all, if you're going to send this app to other people's computers, they need to make sure it's really coming from you—a known and trusted source.

In the bad old days when the Internet was young, just about any website you visited could install and run (or trick you into running) an evil program on your computer. There are still bad folks out there trying to push malware onto unsuspecting computers, but life online is somewhat safer. The safer environment is due in part to certificates—a system that authenticates the source of a program. If a program asks you to install it on your computer, you can check its certificate to see if it's genuinely from, say, Adobe or Microsoft and not from 16-year-old Todd, aka GrimHackerOfAnarchy. If you expect strangers to install your apps on their computers, you should get a code signing certificate from a company like Thawte (www.thawte.com). You'll find they aren't cheap—about $300 for a year or $550 for two years. When you distribute your software, people can check with Thawte or some other certificate ...