Publisher review:Bs_SpamImage is an Anti Form-Spam Code-Image generator class. This script helps to prevent people from writing programs to spam a database with fake automatic form submits.
How does it work?
It adds an image to your form that shows a random code, let's say "A G 8 C Z". the user then needs to type that code into a text field. the way the images are generated it is very hard for an OCR (scanner) or other sort of program to read out the code automatically.
How does it work, technically? - a random code is generated and printed to an image, along with a noisy background. that image is shown on the web page.
- a hidden field is added. the value of the hidden field is an md5 of the generated code, together with a secret key phraze only the webmaster knows. the user can see that md5 "passphraze" but cannot do anything with it.
- when the user submits the form, a new md5 is generated using the user- typed code, along with the secret key phraze, and that is compared to the also submitted original md5. if it matches the user input was ok. no session or cookie is needed.
Functionality:
- lots of settings, check the API.
- specify what chars to use: a-z, A-Z, 0-9 (no special chars)
- ignore case (upper/lower) to make it easier for the user.
- ignore vowels by default so that no 'strange' words are generated by accident.
- ignore confusing chars like l, 1, I
- define the number of characters to use, default is 3-5.
- define image width/height, colors, font size, image format (png/jpg).
Bs_SpamImage is a PHP script for Utilities scripts design by BlueShoes.
It runs on following operating system: Windows / Linux / Mac OS / BSD / Solaris.
Bs_SpamImage is an Anti Form-Spam Code-Image generator class.
Operating system:Windows / Linux / Mac OS / BSD / Solaris
Bs_SpamImage script details 
