Thema: Recaptcha Alternativen gesucht

Index.php:

HTML-Code:

<form name="form" method="post" action="">
<label><strong>Enter Captcha:</strong></label><br />
<input type="text" name="captcha" />
<p><br />
<img src="captcha.php?rand=<?php echo rand(); ?>" id='captcha_image'>
</p>
<p>Can't read the image?
<a href='javascript: refreshCaptcha();'>click here</a>
to refresh</p>
<input type="submit" name="submit" value="Submit">
</form>

Code:

<script>
//Refresh Captcha
function refreshCaptcha(){
    var img = document.images['captcha_image'];
    img.src = img.src.substring(
		0,img.src.lastIndexOf("?")
		)+"?rand="+Math.random()*1000;
}
</script>

Index.php Header

PHP-Code:

<?php
session_start();
$status = '';
if ( isset($_POST['captcha']) && ($_POST['captcha']!="") ){
// Validation: Checking entered captcha code with the generated captcha code
if(strcasecmp($_SESSION['captcha'], $_POST['captcha']) != 0){
// Note: the captcha code is compared case insensitively.
// if you want case sensitive match, check above with strcmp()
$status = "<p style='color:#FFFFFF; font-size:20px'>
<span style='background-color:#FF0000;'>Entered captcha code does not match! 
Kindly try again.</span></p>";
}else{
$status = "<p style='color:#FFFFFF; font-size:20px'>
<span style='background-color:#46ab4a;'>Your captcha code is match.</span>
</p>";    
    }
}
echo $status;
?>

Captcha.php

PHP-Code:

<?php
session_start();
//You can customize your captcha settings here

$captcha_code = '';
$captcha_image_height = 50;
$captcha_image_width = 130;
$total_characters_on_image = 6;

//The characters that can be used in the CAPTCHA code.
//avoid all confusing characters and numbers (For example: l, 1 and i)
$possible_captcha_letters = 'bcdfghjkmnpqrstvwxyz23456789';
$captcha_font = 'monofont.ttf';

$random_captcha_dots = 50;
$random_captcha_lines = 25;
$captcha_text_color = "0x142864";
$captcha_noise_color = "0x142864";


$count = 0;
while ($count < $total_characters_on_image) { 
$captcha_code .= substr(
    $possible_captcha_letters,
    mt_rand(0, strlen($possible_captcha_letters)-1),
    1);
$count++;
}

$captcha_font_size = $captcha_image_height * 0.65;
$captcha_image = @imagecreate(
    $captcha_image_width,
    $captcha_image_height
    );

/* setting the background, text and noise colours here */
$background_color = imagecolorallocate(
    $captcha_image,
    255,
    255,
    255
    );

$array_text_color = hextorgb($captcha_text_color);
$captcha_text_color = imagecolorallocate(
    $captcha_image,
    $array_text_color['red'],
    $array_text_color['green'],
    $array_text_color['blue']
    );

$array_noise_color = hextorgb($captcha_noise_color);
$image_noise_color = imagecolorallocate(
    $captcha_image,
    $array_noise_color['red'],
    $array_noise_color['green'],
    $array_noise_color['blue']
    );

/* Generate random dots in background of the captcha image */
for( $count=0; $count<$random_captcha_dots; $count++ ) {
imagefilledellipse(
    $captcha_image,
    mt_rand(0,$captcha_image_width),
    mt_rand(0,$captcha_image_height),
    2,
    3,
    $image_noise_color
    );
}

/* Generate random lines in background of the captcha image */
for( $count=0; $count<$random_captcha_lines; $count++ ) {
imageline(
    $captcha_image,
    mt_rand(0,$captcha_image_width),
    mt_rand(0,$captcha_image_height),
    mt_rand(0,$captcha_image_width),
    mt_rand(0,$captcha_image_height),
    $image_noise_color
    );
}

/* Create a text box and add 6 captcha letters code in it */
$text_box = imagettfbbox(
    $captcha_font_size,
    0,
    $captcha_font,
    $captcha_code
    ); 
$x = ($captcha_image_width - $text_box[4])/2;
$y = ($captcha_image_height - $text_box[5])/2;
imagettftext(
    $captcha_image,
    $captcha_font_size,
    0,
    $x,
    $y,
    $captcha_text_color,
    $captcha_font,
    $captcha_code
    );

/* Show captcha image in the html page */
// defining the image type to be shown in browser widow
header('Content-Type: image/jpeg'); 
imagejpeg($captcha_image); //showing the image
imagedestroy($captcha_image); //destroying the image instance
$_SESSION['captcha'] = $captcha_code;

function hextorgb ($hexstring){
  $integar = hexdec($hexstring);
  return array("red" => 0xFF & ($integar >> 0x10),
               "green" => 0xFF & ($integar >> 0x8),
               "blue" => 0xFF & $integar);
               }
?>