First, you have to "alter" your database to add "private" field.  Login to your CPanel and then phpMyAdmin; click on
"b2posts" table and then go into the SQL section.  In this section, run the following:

ALTER TABLE b2posts ADD post_private INT(1) DEFAULT 0 NOT NULL;

---

Now in b2template.functions.php file, put the following function anywhere in between "<?php" and "?>":

//checks for the private cookie
function setprivate($password) {
	global $HTTP_COOKIE_VARS, $HTTP_POST_VARS;

	if (isset($HTTP_COOKIE_VARS['private'])) {
		if ($HTTP_COOKIE_VARS['private'] == $password) {
			$private = $HTTP_COOKIE_VARS["private"];
		}
		else {
			setcookie("private", "", time()-36000000, "/", ".michaelpark.net");
		}
	}
	else {
		if (isset($HTTP_POST_VARS['private'])) {
			$private = md5(trim($HTTP_POST_VARS['private']));
			
			if ($private == $password) {
				setcookie("private", $private, time()+36000000, "/", ".michaelpark.net"); //change this to your domain 
			}
			else {
				if (empty($private)) {
					exit ("Please enter the password!<br><br><a href=\"javascript:history.go(-1)\">Go back</a>");
				}
				else {
					exit ("Wrong password!<br><br><a href=\"javascript:history.go(-1)\">Go back!</a>");
				}
			}
		}
	}
	
	return $private;
}

//private entry check
function isprivate($password, $private) {
	global $postdata;
	
	if ($private != $password && $postdata["Private"] == 1) { 
		$isprivate = 1;
	}
	else {
		$isprivate = 0;
	}
	
	return $isprivate;
}

---

In b2functions.php file under get_postdata and get_postdata2 functions, add the following, respectively:

'Private' => $myrow->post_private

and...

'Private' => $row->post_private

Put a comma at the end of the previous line in each function if there are none; for example:

'Karma' => $row->post_karma 

should look like...

'Karma' => $row->post_karma, 

---

In b2edit.form.php file, locate:

<?php echo $form_pingback ?>

Add the following on the next line:

<?php if ($action == 'post' || $action == 'edit') { ?>
<input type="checkbox" class="checkbox" name="post_private" value="1" <?php if ($postdata["Private"] == "1") { 
echo " checked "; } ?>tabindex="7" id="private" /><label for="private"> Private Entry (make only accessible with password)</label><br />
<?php } ?>

---

This is optional, but if you want to "tag" your private entries in b2edit.php file, open "b2edit.showposts.php" file
and locate:

<?php the_title() ?></a></b>

And then add the following after "</b>":

<?php if ($postdata["Private"] == 1) { echo '&nbsp;[private entry]'; } ?>

---

In b2edit.php file, locate:

$post_title = addslashes($HTTP_POST_VARS["post_title"]);

On the next line, add:

$post_private = intval($HTTP_POST_VARS["post_private"]);

Repeat this step for the "edit post" (action) section.

Now modify the INSERT and UPDATE SQL syntaxes as:

$query = "INSERT INTO $tableposts (ID, post_author, post_date, post_content, post_title, post_category, post_private) VALUES ('0','$user_ID','$now','$content','".$post_title."','".$post_category."','".$post_private."')";

...and:

$query = "UPDATE $tableposts SET post_private=\"$post_private\", post_content=\"$content\", post_title=\"$post_title\", post_category=\"$post_category\"".$datemodif." WHERE ID=$post_ID";

Don't copy and paste these lines if you have other hacks installed that insert and update data into the database.

---

In b2config.php file, place:

#private entry password 
$password = "your password";
$password = md5($password);

---

On the top of index.php and/or b2.php files after "include("blog.header.php");", place:

//private cookie check
$private = setprivate($password);

And locate:

<?php while($row = mysql_fetch_object($result)) { start_b2(); ?>

Replace it with:

<?php while($row = mysql_fetch_object($result)) { start_b2(); 

$isprivate = isprivate($password, $private);
?>

And surround "the_content" function like:

<?php 
	if ($isprivate == 1) { 
?>
	This is a private entry.  To view, please enter the password in the field below:<br>
	<form action="<?php echo $siteurl.'/'.$blogfilename.'?p='.$id.'&c=1&more=1'; ?>" method="POST">
	<input type="password" name="private"><input type="submit" value="OK">
	</form>
<?php
	} 
	else { 
		the_content(); 
	} 
?>

You can then control the inclusion of comments link as well as others using the "$isprivate" variable; for example:

<?php
if ($isprivate == 0) { 
	the_title(); 
}
else {
	echo 'Private Entry';
}
?>

...and:

<?php 
if ($isprivate == 0) {
	include("b2comments.php");
	include("b2trackback.php");
	include("b2pingbacks.php"); 
}
?>

...and:

<?php 
	if ($isprivate == 0) {
		comments_popup_link("leave a comment", "1 comment", "% comments"); 
	}
	else {
		echo 'public comments disabled';
	}
?>

In the third case, "public comments disabled" will be displayed if the entry is private AND the user doesn't have the
password (in a cookie).  Therefore, "b2comments.php" does not have to be modified.  Besides, that file can't be loaded
or displayed by its own.  However, if you are using a popup comments page, proceed...

---

In "b2commentspopup.php" file, place the following after "include("blog.header.php");":

//private cookie check
$private = setprivate($password);

And right after "<!-- you can start editing here -->":

<?php 
   if ($private != $password && $postdata["Private"] == "1") { 
?> 
		"<?php the_title() ?>" is a private entry.  To enter comments, please enter the password in the field below:<br> 
		<form action="<?php echo $HTTP_SERVER_VARS["PHP_SELF"]; ?>" method="POST">
		<input type="password" name="private">
		<input type="submit" value="OK">
		</form> 
<?php 
	} 
	else { 
?> 

Then after [comments] "</form>":

<?php 
#private entry closing
	} 
?>

---

If you want to enable your visitors to be able to delete the cookie containing your private password by clicking on a
link, save the following in a separate file and put a link to that file on somewhere on your site, preferably only on
your private entries.

<?php
//resets the variable if it's set
if (isset($HTTP_POST_VARS['private'])) {
	$HTTP_POST_VARS["private"] = '';
}

//deletes the cookie
setcookie("private", "", time()-36000000, "/", ".michaelpark.net"); //change this to your domain

//returns to the previous page
$url = $HTTP_SERVER_VARS["HTTP_REFERER"];
header("Location: $url");
?>

For example:

<?php if ($postdata["Private"] == 1) { echo '&nbsp;[private entry -- <a href="'.$siteurl.'/deletecookie.php">delete cookie</a>]'; } ?>

---

As for RSS and RDF files, I suggest you to delete them from your server.  I modified mine according to the instruction
by the original author of this hack, but I got errors, and I do not know how to fix them.