This can also be easily integrated with Dolphin 7 Look Here
For Dolphin 6 You can swap the current Captcha for a third party one with Captcha Refresh and Audio.
I have done this with Securimage from http://www.phpcaptcha.org/
You can set it to play audio via flash or by clicking an image that plays a wav file.
I used Securimage V 2.0.1 for this tutorial.
Step 1.
Upload Securimage files to a folder called /captcha/ in your main dolphin directory.
Step 2. Set Cookie for D6
Edit /captcha/securimage.php
Find: around line 1000
function generateCode($len)
{
$code = '';
for($i = 1, $cslen = strlen($this->charset); $i <= $len; ++$i) {
$code .= $this->charset{rand(0, $cslen - 1)};
}
return $code;
}
Replace with:
function generateCode($len)
{
$code = '';
for($i = 1, $cslen = strlen($this->charset); $i <= $len; ++$i) {
$code .= $this->charset{rand(0, $cslen - 1)};
}
$hashtext = md5($code);
setcookie('strSec', $hashtext, 0, '/');
return $code;
}
Step 3. Show Captcha Code in D6 Join Form
Edit /templates/base/scripts/BxBaseFormView.php
Find: around line 367
case 'Captcha':
$sCode =
'<img src="' . $site['url'] . 'simg/simg.php" class="form_captcha" /><br /><br />
<input type="text" class="input_text" maxlength="6" name="Captcha" />';
break;
Replace with:
case 'Captcha':
$mtime= md5(time());
$sCode =
'<p> <img id="siimage" align="left" style="padding-right: 5px; border: 0" src="' . $site['url'] . 'captcha/securimage_show.php?sid=' . $mtime . '" />
</p><p style="clear:both">
</p>
<p>Click to hear code:
<a style="border-style: none" href="' . $site['url'] . 'captcha/securimage_play.php" title="Audible Version of CAPTCHA"><img src="' . $site['url'] . 'captcha/images/audio_icon.gif" alt="Audio Version" style="border:none" alt="this.blur()" /></a>
</p>
<p> </p>
<p>Click to swap image:
<!-- pass a session id to the query string of the script to prevent ie caching -->
<a tabindex="-1" style="border-style: none" href="#" title="Refresh Image" alt="document.getElementById(\'siimage\').src = \'' . $site['url'] . 'captcha/securimage_show.php?sid=\' + Math.random(); return false"><img src="' . $site['url'] . 'captcha/images/refresh.gif" alt="Reload Image" border="0" alt="this.blur()" style="vertical-align:middle" /></a>
</p> <br />
<input type="text" class="input_text" maxlength="6" name="Captcha" />';
break;
http://www.boonex.com/unity/blog/entry/Captcha_with_Audio_for_Dolphin_7
Regards