Installing mcrypt extension

mcrypt is necessary if you want to use cookie based authentication with phpymyadmin. Installing mcrypt on CentOS is done with the following command:

yum install php-mcrypt

Once you've done that to install the mcrypt extension, mcrypt should already be added to php.ini. All you need to do to load the php mcrypt extension is to restart your web server like this:

service httpd restart

Now when you log into phpmyadmin, you'll no longer see the message  "Cannot load mcrypt extension. Please check your PHP configuration".

If you've done the two steps above, mcrypt will be installed, enabled in php.ini, and loaded so that encryption will be working properly.