Package: rng-tools

"rng-tools" package binaries on CentOS:

/sbin/rngd /usr/bin/rngtest

You may install this package on CentOS with yum install rng-tools

"rng-tools" package binaries on Debian:

/usr/bin/rngtest /usr/sbin/rngd

You may install this package on Debian with apt-get install rng-tools