Php generates a verification code program with interference

This section describes a verification Generation Program with high security. It can contain interference lines and other content, which can effectively prevent users from using the program to identify the verification code.

The Code is as follows:

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<? Php tutorial /* * Created on 2011-3-11 * Programmer: xiaoyao, QQ: 1045195056 Verify the input value and $ _ SESSION ['check _ pic '] value */ Session_start (); Function RandAscii ($ number) {// $ number generates numbers and letters $ Arr = array ('0', '1', '2', '3', '4', '5', '6', '7 ', '8', '9 ', 'A', 'B', 'C', 'D', 'E', '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; // randomly generated four values are assigned to the session for verification. $ X = 80; $ Y = 24; $ Im = imagecreatetruecolor ($ x, $ y); // create an image $ Bg = imagecolorallocate ($ im, 255,255,255); // sets the color background. Imagefill ($ im, 0, 0, $ bg ); $ Wh = imagecolorallocate ($ im, 255,255, 0 ); $ Gray = 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 )) ); // Color array of words // Draw a border $ Border = imagecolorallocate ($ im, 133,153,193 ); Imagerectangle ($ im, 0, 0, $ x-1, $ y-1, $ border ); For ($ I = 0; $ I <10; $ I ++) {// draw interference lines, 10 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); // font size: 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"); // output image Imagejpeg ($ im ); Imagedestroy ($ im ); ?>

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The Code is as follows:

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<? Php /* * Created on 2011-3-11 * Programmer: xiaoyao, QQ: 1045195056 Verify the input value and $ _ SESSION ['check _ pic '] value */ Session_start (); // enable session If (isset ($ _ POST ['check']) { If ($ _ POST ['check']) { If ($ _ POST ['check'] ==_ _ SESSION ['check _ pic ']) { Echo "the verification code is correct". $ _ SESSION ['check _ pic ']; } Else { Echo "Verification code error". $ _ SESSION ['check _ pic ']; } } } ?> <Form method = post action = ""> <br> <! ---- Link image ---> <Input type = "text" name = "check"> <Input type = "submit" value = "submit"> </FORM>