Ash - there are several reasons you never want to do something like that.
1. You are giving control of your site content over to who knows who.
2. If they wanted to change the content that you receive to maybe porn or something illegal they can do so.
3. Security through obscurity does not work enough to make it a viable option.
4. You would me making your risk greater by choosing such a method.
You could base64 the link but that would mean you would have to decode it before the browser grabbed it and that means you would still be able to see it in source view.
You could do the old javascript trick that we used to do with emails and obfuscate the link using javascript, but still with the use of the tools available in consoles they can easily bypass that.
You could disable the right click menu that includes the view source link using js, but even that is bypassed quite easily.
You could try using a smarty utility to hide it but once it reaches the browser it again is easy to get the info.
You could try htaccess to limit the request referrals to only those that come from the domain itself, but that can cause issues when some browsers send a blank referral.
You could use ionCube to hide the content but oxwall does not support ionCube so its a moot point.
Unless there is something that i have not heard of, there is just no way that i know of to hide, or obfuscate that value and still have it hidden in view source.