diff -urN -X wiki-diff.excluded Wiki.orig/includes/SpecialUserlogin.php Wiki.Captcha/includes/SpecialUserlogin.php
--- Wiki.orig/includes/SpecialUserlogin.php	2006-05-03 06:39:01.000000000 +0200
+++ Wiki.Captcha/includes/SpecialUserlogin.php	2006-05-07 20:18:53.000000000 +0200
@@ -5,6 +5,9 @@
  * @subpackage SpecialPage
  */
 
+/* currently in extension, should be moved to includes ?! */
+require_once('extensions/captcha/captcha-class.php');
+
 /**
  * constructor
  */
@@ -27,7 +30,7 @@
 class LoginForm {
 	var $mName, $mPassword, $mRetype, $mReturnTo, $mCookieCheck, $mPosted;
 	var $mAction, $mCreateaccount, $mCreateaccountMail, $mMailmypassword;
-	var $mLoginattempt, $mRemember, $mEmail, $mDomain;
+	var $mLoginattempt, $mRemember, $mEmail, $mDomain, $mCaptcha;
 
 	/**
 	 * Constructor
@@ -39,6 +42,7 @@
 
 		$this->mType = $request->getText( 'type' );
 		$this->mName = $request->getText( 'wpName' );
+		$this->mCaptcha = $request->getText( 'wpCaptcha' );
 		$this->mPassword = $request->getText( 'wpPassword' );
 		$this->mRetype = $request->getText( 'wpRetype' );
 		$this->mDomain = $request->getText( 'wpDomain' );
@@ -235,6 +239,15 @@
 			return false;
 		}
 
+ 		// 2005-12-30 /TR
+ 		$cap = new captcha();
+ 		if ($cap->verify($this->mCaptcha) != true) {
+ 			/* there should be a new message for i18n @ LanguageXX.php */
+ 			$this->mainLoginForm( "Additional captcha authentication failed!" );
+ 			return false;
+ 		}
+ 		unset($cap);
+
 		if ( !$wgUser->isValidPassword( $this->mPassword ) ) {
 			$this->mainLoginForm( wfMsg( 'passwordtooshort', $wgMinimalPasswordLength ) );
 			return false;
diff -urN -X wiki-diff.excluded Wiki.orig/includes/templates/Userlogin.php Wiki.Captcha/includes/templates/Userlogin.php
--- Wiki.orig/includes/templates/Userlogin.php	2006-04-28 21:32:12.000000000 +0200
+++ Wiki.Captcha/includes/templates/Userlogin.php	2006-05-07 20:15:20.000000000 +0200
@@ -89,6 +89,7 @@
 
 class UsercreateTemplate extends QuickTemplate {
 	function execute() {
+	global $wgScriptPath;
 		if( $this->data['message'] ) {
 ?>
 	<div class="<?php $this->text('messagetype') ?>box">
@@ -163,6 +164,26 @@
 			<?php } ?>
 		</tr>
 		<tr>
+			<td align='right'>
+				<a href="http://en.wikipedia.org/wiki/Captcha">Captcha</a>:
+			</td>
+			<td colspan=2>
+				<img style="display:block;" border="0" id="capimg"
+				src="<?php echo $wgScriptPath; ?>/extensions/captcha/captcha.php"
+				alt="You will need a browser, which can display images."
+				title="Retype the letter-figure combination into the subjacent textfield.">
+			</td>
+		</tr>
+		<tr>
+			<td align='right'>
+				<label for='wpCaptcha'>Retype:</label>
+			</td><td>
+				<input type='text' name="wpCaptcha" id="wpCaptcha"
+					value="" autocomplete="off" size='20' />
+			</td>
+		</tr>
+		<tr>
+
 			<td></td>
 			<td align='left'>
 				<input type='checkbox' name="wpRemember"
diff -urN -X wiki-diff.excluded Wiki.orig/includes/Title.php Wiki.Captcha/includes/Title.php
--- Wiki.orig/includes/Title.php	2006-05-03 06:39:01.000000000 +0200
+++ Wiki.Captcha/includes/Title.php	2006-05-07 20:15:20.000000000 +0200
@@ -824,7 +824,7 @@
 					if ( $query == '-' ) {
 						$query = '';
 					}
-					$url = "{$wgScript}?title={$dbkey}&{$query}";
+					$url = "{$wgScript}{$dbkey}&{$query}";
 				}
 			}