$conf['title'] = 'Mon Wiki';
$conf['lang'] = 'fr';
$conf['template'] = 'monobook';
$conf['dformat'] = 'd/m/Y H:i';
$conf['useacl'] = 1;
$conf['authtype'] = 'mybb';
$conf['superuser'] = '@admin';
$conf['htmlok'] = 1;
$conf['phpok'] = 1;
$conf['tpl']['monobook']['mb_bc_loc'] = 'top';
$conf['tpl']['monobook']['mb_hbc_loc'] = 'top';

<?php
/**
 * MyBB auth backend
 *
 * Uses external Trust mechanism to check against MyBB's
 * user cookie.
 *
 */

// necessary to access MyBB vars & functions
define("IN_MYBB", 1);
// get (and save) current dir
$cwd = getcwd();

// change dir to MyBB forum to init vars & functions
// modify below to point to MyBB forum folder:
chdir('../MyBB'); // path to MyBB

// required MyBB includes
require_once 'global.php';
require_once 'inc/config.php';
require_once "inc/functions_user.php";

// back to to current dir
chdir($cwd);

// based on auth_basic
define('DOKU_AUTH', dirname(__FILE__));
require_once(DOKU_AUTH.'/basic.class.php');

#dbg($GLOBALS);
#dbg($mybb->user);

class auth_mybb extends auth_basic {

  /**
   * Constructor.
   *
   * Sets additional capabilities and config strings
   */
  function auth_mybb(){
   
    // to use trustExternal and Logoff
    $this->cando['external'] = true;
    $this->cando['logoff']   = true;
   
  }

  /**
   * Just checks against the $mybb->user variable
   */
  function trustExternal($user,$pass,$sticky=false){
    global $USERINFO, $conf; // docuwiki
    global $mybb, $db, $config; // MyBB

    $sticky ? $sticky = true : $sticky = false; //sanity check

          // someone used the login form
          if(!empty($user)){
                // use of MyBB internal function to validate password
          $user = validate_password_from_username($user,$pass);
        if(!$user['uid']){
               //invalid credentials - log off
               auth_logoff();
               return false;
               }
        // password is OK, setting cookie...
        my_setcookie('loginattempts', 1);
          $db->delete_query(TABLE_PREFIX."sessions", "ip='".$db->escape_string($session->ipaddress)."' AND sid != '".$session->sid."'");
          $newsession = array(
                "uid" => $user['uid'],
                  "loginattempts" => 1,
                  );
          $db->update_query(TABLE_PREFIX."sessions", $newsession, "sid='".$session->sid."'");
          // Temporarily set the cookie remember option for the login cookies
          $mybb->user['remember'] = $user['remember'];
          my_setcookie("mybbuser", $user['uid']."_".$user['loginkey'], null, true);
          my_setcookie("sid", $session->sid, -1, true);
          }

          if(isset($mybb->user['uid'])){
            // okay we're logged in - set the globals
          $USERINFO['pass'] = $mybb->user['password'];
          $USERINFO['name'] = $mybb->user['username'];
          $USERINFO['mail'] = $mybb->user['email'];
          $USERINFO['grps'] = array('@user', '@admin'); // here I don't know how... (just for testing)
         
          $_SERVER['REMOTE_USER'] = $mybb->user['username'];
          $_SESSION[DOKU_COOKIE]['auth']['user'] = $mybb->user['username'];
          $_SESSION[DOKU_COOKIE]['auth']['info'] = $USERINFO;
          return true;
          }
    // to be sure
    auth_logoff();
    return false;
}

  /**
   * remove cookie on logout
   */
  function logOff(){
    global $mybb;
    my_unsetcookie("mybbuser");
    my_unsetcookie("sid");
  }
}