math captcha php

Why can someone else use the verification code? Why can someone else use the verification code? The following is the code for obtaining the verification code. is the verification code too simple? how can we make it more complicated? /** *

Copy CodeThe code is as follows: //-------------------------------------File Description: Mathematical Operation Verification CodeFile Author: Jesse LeeLast update: 2008-09-07//-------------------------------------Session_Start ();$sessionvar = '

PHP generates an example of a picture verification code to explain, In this paper, we demonstrate 5 kinds of verification codes, and describe the function of generating verification code. PHP generated Verification code principle: Through the GD

PHP generated image verification code-with five kinds of verification code, Previous output verification code used a method, in the foreground with JS generated verification code string, and then passed to the background with PHP output

PHP graphic verification code sharing, php graphic Verification Code Effect: Myvcode. class. php: class that encapsulates the verification code /** File: myvcode. class. php* Verification Code Class, Class Name Vcode*/Class Vcode{Private $ width;/*

Prepare the canvas $im = Imagecreatetruecolor (500, 300); Preparing Paint $black = imagecolorallocate ($im, 0, 0, 0); $white = Imagecolorallocate ($im, 255, 255, 255); Background filled with black Imagefill (

Before the output verification code used a method, in the foreground with JS to generate a code string, and then passed to the background with PHP output CAPTCHA code image. This does not require the use of $_session to pass the verification code

Source: 3 dcaptchaHttp://www-personal.umich.edu /~ Mressl/3 dcaptcha/ Http://code.google.com/p/3dcaptcha/ Official logo   This example is complete.ProgramTranslation, no additional processing. C #AlgorithmImplementation /*** Dcaptcha

System Requirements : php5.3.3 above versionProject directory:/VAR/WEB/NEWZF2 preparatory work :Download the Zftool.phar and Zftool modules. To/var/webZftool.phar Address: Https://packages.zendframework.com/zftool.pharAddress of the Zftool module:

In IE, the verification code will not be refreshed, but there is no problem with Google and other browsers. The solution is to add a random parameter after the switching address of the Verification Code. Today, we found it in IE when doing the