这里介绍了一款安全性比较高的验证生成程序,可以带干扰线等内容,可以有效的防止用户用程序识别验证码的难度了,代码如下:

1. <?php
2. /*
3. * Created on 2011-3-11
4. * Programmer : xiaoyao, QQ:1045195056
5. 验证通过判断输入值与$_SESSION['check_pic']值
6. */
7. session_start();
8. function RandAscii($number){//$number产生数字和字母个数
9. $arr=array('0','1','2','3','4','5','6','7','8','9',
10. 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','w','v','u','x','y','z');
11. for ($i=1;$i<=$number;$i++)
12. {
13. $rand= $rand.$arr[rand(0,35)];
14. }
15. return $rand;
16. }
17. $rand=RandAscii(4);
18. $_SESSION['check_pic']=$rand;//随机产生的四个数赋值session中，用于验证。
19. $x=80;
20. $y=24;
21. $im=imagecreatetruecolor($x,$y);//创建图片
22. $bg=imagecolorallocate($im,255,255,255);//设置颜色背景
23. imagefill( $im,0,0,$bg);
24. $wh=imagecolorallocate($im,255,255,0);
25. $grey=imagecolorallocate($im,128,128,128);
26. $yellow=imagecolorallocate($im,255,255,0);
27. $red=imagecolorallocate($im,0,255,0);
28. $foregroundArr = array(imagecolorallocate($im, rand(0, 20), rand(0, 20), rand(0, 20)),
29. imagecolorallocate($im, rand(0, 20), rand(0, 10), rand(245, 255)),
30. imagecolorallocate($im, rand(245, 255), rand(0, 20), rand(0, 10)),
31. imagecolorallocate($im, rand(245, 255), rand(0, 20), rand(245, 255))
32. );//字颜色数组
33. //画边框
34. $border = imagecolorallocate($im, 133, 153, 193);
35. imagerectangle($im, 0, 0, $x - 1, $y - 1, $border);
36. for($i=0;$i<10;$i++){ //画干扰线，10条
37. imageline($im,rand(0,60),2,rand(0,60),20,$yellow);
38. }
39. for($j=0;$j<100;$j++){
40. imagesetpixel($im,rand()%76,rand()%20,$red);
41. }
42. //imagestring($im,6,15,8,$rand,$wh);//字体大小1-5
43. imagettftext($im, 14,rand(30, -30), 5, rand(15, 18) ,$foregroundArr[rand(0,3)], 'C:WindowsFontsArial.ttf',$rand[0]);
44. imagettftext($im, 14,rand(50, -50), 24, rand(15, 18),$foregroundArr[rand(0,3)], 'C:WindowsFontsArial.ttf',$rand[1]);
45. imagettftext($im, 14,rand(50, -50), 43, rand(15, 18) ,$foregroundArr[rand(0,3)], 'C:WindowsFontsArial.ttf',$rand[2]);
46. imagettftext($im, 14,rand(30, -30), 62, rand(15, 18),$foregroundArr[rand(0,3)], 'C:WindowsFontsArial.ttf',$rand[3]);
47. //开源代码phpfensi.com
48. header("Content-type: image/jpeg");//输出图片
49. imagejpeg($im);
50. imagedestroy($im);
51. ?>

调用方法,代码如下:

1. <?php
2. /*
3. * Created on 2011-3-11
4. * Programmer : xiaoyao, QQ:1045195056
5. 验证通过判断输入值与$_SESSION['check_pic']值
6. */
7. session_start();//开启session
8. if(isset($_POST['check']))
9. {
10. if($_POST['check'])
11. {
12. if($_POST['check']==$_SESSION['check_pic'])
13. {
14. echo " 验证码正确".$_SESSION['check_pic'];
15. }
16. else
17. {
18. echo " 验证码错误".$_SESSION['check_pic'];
19. }
20. }
21. }
22. ?>
23. <FORM METHOD=POST ACTION="">
24. <img src="index.php"><br> <!----链接图片--->
25. <input type="text" name="check" >
26. <input type="submit" value="提交">
27. </FORM>