PHP Graphical Digital Verification Code

the following code I debug all through. Run authpage.php.





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/* 





* Filename:authpage.php





*/ 





Srand (double) microtime () *1000000);





//Verify that user input is consistent with the verification code





if (isset ($_post[' authinput ') )





{ 








if (strcmp ($_post[' authnum '],$_post[ ' authinput ']) ==0)





echo "Verify success!" "; 





Else





echo "Validation failed! "; 





} 





//Generate a new four-bit integer verification code





while (($authnum =rand ()%10000) <1000);





?>





<form action=authpage.php method=post>





<table>





Please enter the verification code: <input type=text name=authinput style= "width:80px" ><br>





<input type=submit name= "Authentication" value= "Submit authentication Code" >





<input type=hidden name=authnum value=< echo $authnum;?>>





>





</table>





</form>





------------------------------------------------------------------------------------------------------- ------ 





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/* 





* Filename:authimg.php





*/ 


//Generate CAPTCHA picture


Header ("Content-type:image/png");





Srand (double) microtime () *1000000);





$im = imagecreate (58,28);





$black = imagecolorallocate ($im, 0,0,0);





$white = imagecolorallocate ($im, 255,255,255);





$gray = imagecolorallocate ($im, 200,200,200);





Imagefill ($im, 68,30, $gray);





//Draw four-bit integer captcha into the picture





imagestring ($im, 5, 8, $HTTP _get_vars[' Authnum '), $white);





for ($i =0; $i <50; $i + +)//Add interference pixel





{ 





Imagesetpixel ($im, Rand ()%70, Rand ()%30, $gray);





} 





imagepng ($im);





Imagedestroy ($im);





?>


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java->struts