Centos Php Mcrypt

First get the epel repository. To do this go to the page fedoraproject.org and choose the epel-release under the header "How can I use these extra packages?".

After that, download the package to a location you like. Open command line, get into the directory that you just placed the new rpm.

rpm -i epel-release*.rpm

This will add the epel repository. Next step is to let yum install what we need..

yum install php-mcrypt

And restart your apache..

This has done the trick in my centos..