Updated: 02/20/2007

Math Captcha image validation

With all the Captcha decoders these days, its impossible to build a solid Captcha image validator with a string. The solution? Have a captcha that asks simple math addition questions! Decoders are not very good at breaking these. This tutorial will show you how to make a basic math CAPTCHA validtion form. This requires that you have the GD library for PHP installed to work.

• Categories
  • PHP →
  • Tips and Tutorials →
  • Security
• Platforms
  • Linux,
  • FreeBSD
• Licenses
  • GPL
• Author
  • Yinan Chen