How to encrypt all external links

hello everybody,
i would like to hide or mask all the external links from my website, for example :

if i post a list of youtube’s videos:
http://www.youtube.com/sdfgsdgdfgfsdfg

i would like they will all appear as:
http://www.mywebsite.com/protect00/asdgasdfgfasgfd

so maybe if someone will copy my links i ll just need to change the tag “protect00” in 01… so all the stolen link will redirect to my 404 page.

i’ve found sth similar but the external links is still visible somehow
(like this : http://www.mywebsite.com/goto.php:www.youtube.com/sdfgsdgdfgfsdfg and

i don’t want sth like that!

)

i hope my request to be clear, thanks you all