root@Zeus:~# apt-get install php5-mcrypt
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  linux-headers-3.13.0-36 linux-headers-3.13.0-36-generic
  linux-image-3.13.0-36-generic linux-image-extra-3.13.0-36-generic
Use 'apt-get autoremove' to remove them.
The following NEW packages will be installed:
  php5-mcrypt
0 upgraded, 1 newly installed, 0 to remove and 27 not upgraded.
Need to get 15.4 kB of archives.
After this operation, 102 kB of additional disk space will be used.
Get:1 http://mirrors.digitalocean.com/ubuntu/ trusty/universe php5-mcrypt amd64 5.4.6-0ubuntu5 [15.4 kB]
Fetched 15.4 kB in 0s (38.0 kB/s)
Selecting previously unselected package php5-mcrypt.
(Reading database ... 117325 files and directories currently installed.)
Preparing to unpack .../php5-mcrypt_5.4.6-0ubuntu5_amd64.deb ...
Unpacking php5-mcrypt (5.4.6-0ubuntu5) ...
Setting up php5-mcrypt (5.4.6-0ubuntu5) ...
root@Zeus:~# php5enmod mcrypt
root@Zeus:~# service nginx restart
 * Restarting nginx nginx                                                [ OK ]
root@Zeus:~#