It's probably at this point you're wondering what to do next. Unless you REALLY REALLY like the theme, delete it and find another. Otherwise, you can take the steps to remove the base64 code from your site. Unfortunately, the actual removal of base64 code goes beyond the scope of this tutorial (I will have a separate one soon), but there are some precautions you can take to avoid it altogether.

1. Only download/install themes from a trusted site. Naturally Wordpress.org is trusted as is the built-in theme installer that's part of your Wordpress package.

2. Only download/install themes from the developer site itself. This is with exception of the above precaution. I know this spells doom for some who have theme sites as a niche, but you're literally crossing busy highway traffic here. Some shady developers will take a theme, add their base64 code to it, repackage it, then redistribute it.

3. NEVER EVER EVER pirate themes or otherwise find a premium theme offered for free from a third-party site. This goes hand-in-hand with the second precaution. If the theme is an at-cost premium theme, PAY FOR IT. This is not a moral issue moreover an issue of the theme being tampered with. It can get extremely dangerous from here, not only can your SEO and ranking get destroyed, but it may open up your site to hackers and other attacks.

Bottom line, if you look hard enough, you will find a theme that suits your needs without having this destructive code implemented with it.

I hope this tutorial helps you develop a strong site that's not hampered by ruinous code.