THE FIRST STEP

First of all, Clickbank protection is decent as it is. If you want to keep your customers from passing thank you page URL around to friends, there are a couple of things you can do.

Login to your Clickbank account: http://www.clickbank.com/login.html

At top there's a link that says "Click HERE to modify your account". Click on link.

On this page there are two links at top, but one says "Click HERE to modify your account." Click on this one.

You should be at page that allows you to edit prices of all your Clickbank products. Scroll down to bottom where it says:

Secret key (up to 16 letters & digits)

You should see a text box here. If it's empty, choose a secret key, type it in and remember it. It can be anything you want, but it should be different than your Clickbank password.

"COOKIE CUTTER" TOOLS

If you've looked around Clickbank site you'd know that Clickbank offers some friendly pieces of code in a few different programming languages like Perl and PHP that can help you protect your downloads. Basically this is what happens:

* Your order link contains what's called a "seed". This is just a word or a piece of text, which can be anything you want.

* Your customer clicks on order link and pays.

* Clickbank takes that seed, and uses your secret key on it -- basically mashes two together and does a bunch of crazy stuff to come up with a garbled piece of junk. But this a garbled piece of junk that can ONLY come from this seed and secret key. You change value of seed or secret key even a little and this "hash" changes.

* The seed and hash are passed back to thank you page where your Clickbank script sits. (We have secret key added to your script, and it never changes, so it doesn't need to be handed to us by Clickbank.) This Clickbank script takes seed and secret key and does same crazy shit Clickbank did to us to compute your own hash.

Clickbank calls this their "cbpop" or Clickbank Proof of Purchase.

The hash was something we figured out on your own and hash Clickbank are compared. If they match, we're in business because customer here really did buy from us.. The customer can't figure this out on his or her own because they never actually saw secret key. (And no, you can't "reverse" a hash to figure out original secret key.)

If you get nothing out of what I just told you, remember this: it's almost impossible for anyone to figure out right Proof of Purchase code without that secret key.

USING SOMEONE ELSE'S CODE

This is PHP function they give us:

function cbValid($seed, $cbpop, $secret_key) { // A bunch of stuff in here... }

This function cbValid takes three parameters: $seed, $cbpop, and $secret_key. The script goes through that last step of ours I explained above, does crazy shit and then compares result to one given to us by Clickbank.

Now we need to figure out what to do if your customer really didn't pay. The easiest thing to do, is just stop script in its tracks, preventing page under it from loading.

if (!cbValid($seed, $cbpop, $secret_key)) die();

The exclamation point means "not". We're saying, first try this...

cbValid($seed, $cbpop, $secret_key)

... pass seed, proof of purchase, and secret key into your black box. If function tells us NO, do rest. In this case, "die". Die stops everything immediately, so if you have HTML or PHP code below that line, it won't be looked at if Clickbank validation fails.

The "proper" way to grab $seed from query string is this way:

if (!cbValid($_GET["seed"], $_GET["cbpop"], $secret_key)) die();

You could also redirect user to an error page of yours if you like:

if (!cbValid($_GET["seed"], $_GET["cbpop"], $secret_key)) { header("Location:http://www.your.host/error.html"); die(); }

Instead of $seed and $cbpop we use $_GET["seed"] and $_GET["cbpop"]. This is because variables don't appear magically out of thin air, they really appear in URL as http://www.your.url est.php?seed=SOMESEED&cbpop=SOMEPOP. We want these values to be taken out of URL.

USE MINE

Here's a zip file containing your cb.php script: http://www.jumpx.com utorials/clickbank/cb.zip

Save it, unzip it, and open cb.php. Near top should be a line such as:

$secret_key = "YOUR_SECRET_KEY";

Change YOUR_SECRET_KEY to that secret key you set in Clickbank control panel.

Now, for usage... your thank you pages will have to end in .php here. Like, thankyou.php (and now it doesn't matter if they have obvious names or not -- because they'll be thoroughly inaccessible to thieves. Remember, you can simply rename your HTML pages so they end in .php and they'll still work just fine.

Put this line at top of you thank you page script:

Be sure to upload cb.php to same folder as your thank you page. Now, when someone goes to thank you page, first thing thank you script will do is run everything in cb.php, and cb.php will take data Clickbank has passed to see if it matches.

You're going to have to change your Clickbank order links a little. This is what they should look like now:

http://www.clickbank.net/sell.cgi?link=YOUR_CLICKBANK_ID/YOUR_PRODUCT_ID/YOUR_PRODUCT_NAME&seed=YOUR_SEED

Replace YOUR_CLICKBANK_ID with, of course, your Clickbank ID and YOUR_SEED with seed you want to use. This can be anything, something simple that's short and one word like product name. But NOT your secret key.

YOUR_PRODUCT_ID is number Clickbank shows to left of each thank you page as you add it. When you're testing, be sure to set price at $0.00. Once everything's in place you can raise price of item to $19.95 or $29.95 or whatever it's priced at.

http://www.clickbankguide.com/merchant.htm#account will explain everything if you're a Clickbank newbie.

COULDN'T THE DOWNLOAD URL, HASH, AND RECEIPT BE SHARED?

A wrapper is like a middleman. Using htaccess you can tell your web server to "forward" certain files to PHP scripts of yours. When a visitor tries to load an image in their browser, you could activate a script that adds a watermark to image. When an HTML page is loaded you could query an IP-to-country database and have your HTML pages translated into native language of your visitor's country-of-origin.

Every file in a folder, or all files of a certain type in a folder, can be instructed to go through a PHP script.

TORTILLA WRAP

Pretend you host several affiliate sites, or a full-blown hosting service like Geocities. Most sites running on free hosting services have some kind of advertisement owners use to generate revenue. These aren't applied voluntarily by users of these services. The ads don't even show up on their source files, just when displayed on web.

It's possible to replicate this feature using less than 10 lines of PHP and htaccess code. To start off, make a folder on your web host called "header". Create a new text file and enter following:

AddHandler headered .htm AddHandler headered .html

Action headered /header/header.php

This designates files with extension ".htm" and ".html" to a type called "headered". The name "headered" can really be anything, it's just a way of labeling a group of files. The last line there tells web server that if any of file types in group called "headered" are called, we should instead execute script "/header/header.php". This is relative path, so if your URL is http://your.host, this will run http://your.host/header/header.php.

That's all you've got to do for htaccess file. Save that as "htaccess.txt" -- we'll get back to it later.

For actual wrapper, create a new text file with standard tags, then assign your header and footer file names to variables called $header and $footer.

$header = "header.html"; $footer = "footer.html";

Redirecting a user to our script doesn't pass its contents to it, just filename. If you call phpinfo() in your script and scroll to bottom you can see all server variables which give us name. The element "REQUEST_URI" in $_SERVER gives us relative path (/header/sample.html), but we want full system path since we're going to be reading actual file (/home/username/wwwroot/your.host/header/sample.html), which is "PATH_TRANSLATED".

$file = $_SERVER["PATH_TRANSLATED"];

The name of file that just tried to be shown is now stored in variable $file. Three simple things are left: output header, output actual file, then output footer.

readfile($header); readfile($file); readfile($footer);

That's it. Here's entire header.php file:

$header = "header.html"; $footer = "footer.html";

$file = $_SERVER["PATH_TRANSLATED"]; readfile($header); readfile($file); readfile($footer);

?>

All that, in just nine lines of code. Download it here: http://www.jumpx.com utorials/wrapper/header.zip

That contains htaccess file and PHP wrapper script, along with a sample header, footer, and a test page. Upload all five files to your web host, chmod htaccess.txt to 0755 then rename it to ".htaccess". It might disappear from your directory listing which is okay, it should still be there.

Load, in your browser, copy of sample.html residing on your web server. The text "This is my header" should appear at top while "This is my footer" should show on bottom. If you open up actual file called sample.html, you'll see that these actually aren't there. They've been added in by script all HTML files in folder "header" must now pass through.

This is how wrappers work. Certain things, like adding custom headers and footers are done "on fly" without modifying your original file. You'll get same effect if you create other HTML files and upload them to this folder.

Files without ".html" or ".htm" extensions, such as text files or images, won't show these headers or footers. This is a good thing because text files aren't part of presentation on a web site and adding extra text to images will corrupt them. It affects all HTML files within your /headers folder, and none of files outside of it.

If you wanted, you could add or remove any file extensions you want, just by adding or taking away those "AddHandler" lines.

To get everything back to normal, either delete your .htaccess file or upload a blank .htaccess file in that folder, and all will be well again.

SHRINK-WRAP

The same basic formula can be applied again for other uses -- HTTP compression, for example. This was an idea that used to be impractical because computers ran at slower speeds, and is now obsolete because of broadband technologies (DSL and cable).

It works like this: when an HTML page is loaded, web server instead gives visitor a zipped or compressed version of that page. The visitor downloads that file, which of course takes up less space than real thing and downloads in less time, then unzips it and displays original page.

In this age of lighting fast DSL lines, there's almost no noticeable difference. However, if you have a site that hosts large files whose audience is mostly dialup users, it might be something to look into.

Make a new folder called "compress". Create your htaccess file again, just as before, but set extensions to include .htm, .html, and .txt. (The group name, folder name, and script name have nothing to do with one another, you can name any of these whatever you like -- I just like things to match.)

Our wrapper script for this should be called "compress.php". That's what I'm naming mine. This means htaccess file you have should look as follows:

AddHandler compress .html AddHandler compress .htm AddHandler compress .txt

Action compress /compress/compress.php