Package: mcrypt

"mcrypt" package binaries on CentOS:

/usr/bin/mcrypt /usr/bin/mdecrypt

You may install this package on CentOS with yum install mcrypt

"mcrypt" package binaries on Debian:

/usr/bin/crypt /usr/bin/mcrypt /usr/bin/mdecrypt

You may install this package on Debian with apt-get install mcrypt