Discuz Forum How to prevent people from malicious irrigation

Now the forum is very powerful irrigation tools. Can realize automatic registration, automatic identification code, automatic posting.
Discuz Forum with a lot of people, they specifically for the Discuz Forum Verification Code has been studied. The above verification code recognition rate reached more than 90%.
The verification code is designed to prevent people from flooding.
But the verification code is now intelligently recognized by the program.
So there's a simple way.
We can artificially increase the complexity of the verification code.
Make the program more difficult to identify the verification code.
In this respect Discuz has left a very simple interface
Method is to enter
In the installation directory of the Forum
Images/common
Find the pictures of those verification codes.
Picture naming is Number0.gif-number9.gif
These pictures you can modify in Photoshop.
This allows us to manually modify the displayed verification code to a complex point.
I processed the verification code image has been uploaded to the group share.
Each verification code uses a glyph that is not used. and made a distortion.
I don't think there are many programs that can intelligently identify

========== arranged in QQ chat record. (I've made good pictures and I can't upload attachments here.) Can contact me directly to you can also go to bbs.ynjob.net on the effect of verification code)