Zend certified PHP/Magento developer

mcrypt deprecated message. How do I switch to an alternative like openssl?

I’m getting this error that mycrypt is deprecated. I’ve heard I should use openssl. But I’m not sure how would I go about this in terms of my Magento 1.9 setup. Can I get some insight? Also how serious is this problem?

ERR (3): Deprecated functionality: Function mdecrypt_generic() is deprecated in /home/customer/www/sciencellonline.com/public_html/lib/Varien/Crypt/Mcrypt.php on line 130

Thanks