Two URLs pointing to same content

Joomla 2.5 Site: www.orsyp.com/resource-center/white-papers/

For instance, I noticed that when you filter for "White Papers" the URL is: www.orsyp.com/index.php?option=com_custo...ntent%3A122%2Cconten

When you click on the "White Papers" tag it brings you to this: www.orsyp.com/component/customproperties/tag/1/

I tried adding a redirect from the long one to the shorter one in my .htaccess, but it doesn't do anything. The same issue applies to all tags. How can I redirect these URLs to make them friendly?

The URL format can be changed with parameter 'Url Format => ' in main Custom Properties configuration.

The two URLs you posted as examples, although leading to the same result set, are inherently different:
The former is the result of a search form, where many criteria can be chosen at the same time. The latter is an hyperlink pointing to a single tag.

The long "URL" can't be shortened.