This is a generic question that a lot of people have asked that I can't seem to find. If I wanted to change the url for my check out to something else, what are my options?
URL in question: component/virtuemart/cart?Itemid=0
Is there a .htaccess file that I can use to secure the site from hacking?
I have not noticed anyone asking that question before. Any itemid at the end of that url will display the cart. You can alter the dispayed url with SEF.
.htaccess cannot on its own secure a site from hackers. Most important is to ensure the latest secure versions of Joomla and all installed templates, components, modules and plugins are always used. All the hacked sites I have encountered have been due to not keeping versins updated.
There is an "Ultimate Htaccess File for Joomla" that you could possibly use, although some of the code will almost certainly prevent an on-line store from working. http://pbwebdev.com/blog/ultimate-htaccess-file-for-joomla