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captcha.php

@@ -0,0 +1,43 @@
+<?php
+session_start();
+
+header('Content-type: image/png');
+header('Cache-Control: no-cache, no-store, must-revalidate');
+header('Pragma: no-cache');
+header('Expires: 0');
+
+$width = 120;
+$height = 40;
+$chars = '23456789ABCDEFGHJKLMNPQRSTUVWXYZ';
+$code = '';
+
+for ($i = 0; $i < 4; $i++) {
+    $code .= $chars[rand(0, strlen($chars) - 1)];
+}
+
+$_SESSION['captcha'] = $code;
+
+$image = imagecreate($width, $height);
+$bg_color = imagecolorallocate($image, 255, 255, 255);
+$text_color = imagecolorallocate($image, 0, 0, 0);
+$noise_color = imagecolorallocate($image, 200, 200, 200);
+
+for ($i = 0; $i < 100; $i++) {
+    imagesetpixel($image, rand(0, $width), rand(0, $height), $noise_color);
+}
+
+for ($i = 0; $i < 5; $i++) {
+    imageline($image, rand(0, $width), rand(0, $height), rand(0, $width), rand(0, $height), $noise_color);
+}
+
+$font = 5;
+$x = 10;
+for ($i = 0; $i < 4; $i++) {
+    $char_color = imagecolorallocate($image, rand(0, 150), rand(0, 150), rand(0, 150));
+    imagestring($image, $font, $x, rand(8, 12), $code[$i], $char_color);
+    $x += 25;
+}
+
+imagepng($image);
+imagedestroy($image);
+?>