Haveged
The haveged project is an attempt to provide an easy-to-use, unpredictable random number generator based upon an adaptation of the HAVEGE algorithm. Haveged was created to remedy low-entropy conditions in the Linux random device that can occur under some workloads, especially on headless servers.
Alternative
Unless you have a specific reason to not trust any hardware random number generator on your system, you should try to use them with the rng-tools first and if it turns out not to be enough (or if you don't have a hardware random number generator available), then use Haveged.
List available entropy
If you're not sure, whether you need haveged, run:
# cat /proc/sys/kernel/random/entropy_avail
This command shows you how much entropy your server has collected. If it is rather low (<1000), you should probably install haveged. Otherwise cryptographic applications will block until there is enough entropy available, which eg. could result in slow wlan speed, if your server is a Software access point.
You should use this command again to verify how much haveged boosted your entropy pool after the installation.
Installation
Install the haveged package from the official repositories.
Service
The package provides haveged.service
, see systemd for details.