這裡介紹了一款安全性比較高的驗證生成程序，可以帶干擾線等內容，可以有效的防止用戶用程序識別驗證碼的難度了。 代碼如下 復制代碼
<?php教程
/*
* Created on 2011-3-11
* Programmer : xiaoyao, QQ:1045195056
驗證通過判斷輸入值與$_SESSION['check_pic']值
*/
session_start();
function RandAscii($number){//$number產生數字和字母個數
$arr=array('0','1','2','3','4','5','6','7','8','9',
'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','w','v','u','x','y','z');
for ($i=1;$i<=$number;$i++)
{
$rand= $rand.$arr[rand(0,35)];
}
return $rand;
}
$rand=RandAscii(4);
$_SESSION['check_pic']=$rand;//隨機產生的四個數賦值session中，用於驗證。
$x=80;
$y=24;
$im=imagecreatetruecolor($x,$y);//創建圖片
$bg=imagecolorallocate($im,255,255,255);//設置顏色背景
imagefill( $im,0,0,$bg);
$wh=imagecolorallocate($im,255,255,0);
$grey=imagecolorallocate($im,128,128,128);
$yellow=imagecolorallocate($im,255,255,0);
$red=imagecolorallocate($im,0,255,0);
$foregroundArr = array(imagecolorallocate($im, rand(0, 20), rand(0, 20), rand(0, 20)),
imagecolorallocate($im, rand(0, 20), rand(0, 10), rand(245, 255)),
imagecolorallocate($im, rand(245, 255), rand(0, 20), rand(0, 10)),
imagecolorallocate($im, rand(245, 255), rand(0, 20), rand(245, 255))
);//字顏色數組
//畫邊框
$border = imagecolorallocate($im, 133, 153, 193);
imagerectangle($im, 0, 0, $x - 1, $y - 1, $border);
for($i=0;$i<10;$i++){ //畫干擾線，10條
imageline($im,rand(0,60),2,rand(0,60),20,$yellow);
}
for($j=0;$j<100;$j++){
imagesetpixel($im,rand()%76,rand()%20,$red);
}
//imagestring($im,6,15,8,$rand,$wh);//字體大小1-5
imagettftext($im, 14,rand(30, -30), 5, rand(15, 18) ,$foregroundArr[rand(0,3)], 'C:WindowsFontsArial.ttf',$rand[0]);
imagettftext($im, 14,rand(50, -50), 24, rand(15, 18),$foregroundArr[rand(0,3)], 'C:WindowsFontsArial.ttf',$rand[1]);
imagettftext($im, 14,rand(50, -50), 43, rand(15, 18) ,$foregroundArr[rand(0,3)], 'C:WindowsFontsArial.ttf',$rand[2]);
imagettftext($im, 14,rand(30, -30), 62, rand(15, 18),$foregroundArr[rand(0,3)], 'C:WindowsFontsArial.ttf',$rand[3]);
header("Content-type: image/jpeg");//輸出圖片
imagejpeg($im);
imagedestroy($im);
?>
調用方法
代碼如下 復制代碼 <?php
