Some theme authors embed links in an encoded footer making it difficult to understand what is happening in the footer. Note: this type of encoded content could be malicious as well as just a copyright banner!
The best course of action is to avoid using encrypted themes entirely. There are a large number of free themes available without such potentially malicious code in them.
Nevertheless, here's a method to decode (figure out) and correct the footer so there is no encoding.
In your index.php find the line that says <?php get_footer(); ?>. Above and below it add marker text like this:
<!-- Evil Footer Devil FOUND --> <?php get_footer(); ?> <!-- Evil Footer Devil BEGONE -->
Now visit your site, view source (e.g. View->Page Source in Firefox), and copy the HTML between those two markers. Rename your footer.php and make a new copy of footer.php with that HTML code. Then change it to your hearts content. Remember to insert the <?php wp_footer(); ?> before </body> tag.
Keep in mind that if your theme's license does not permit this, then don't do it. If that's the case please consider finding a new theme.
Posted in: WordPress