I built a captcha for a friend a while back for a shopping site, obviously it was too simple to be corrupted so I built this new one last night. It was not perfect though, as I don’t have enough knowledge to create dynamic fonts.
Under Ubuntu it is easy to get things work – install php5-gd, luckily it brought couple of fonts and then the script works like a charm. Under my friend’s machine I need to install some extra packages to get TrueType fonts, but it is not that hard.
Let’s see how this works, I believe the captcha is a little bit hard to be read, but it can block spammers.