I noticed haveged is still installed and enabled by default in EnOS, but general consensus seems to suggest it’s not needed/useful anymore (and cat /proc/sys/kernel/random/entropy_avail always returns 256 anyway)
Some relevant related read:
Starting from Linux kernel v5.4, the HAVEGED inspired algorithm has been included in the Linux kernel (see the LKML article and the Linux Kernel commit). Additionally, since v5.6, as soon as the CRNG (the Linux cryptographic-strength random number generator) gets ready,
/dev/randomdoes not block on reads anymore (see this commit).
I’m happy that these changes made it into the mainline kernel. It’s pleasing to see that the main idea behind HAVEGED has sustained time test - it was published already in 2003 here. I’m also glad that the HAVEGE algorithm is being further explored and examined - see the CPU Jitter Random Number Generator.
Please note that while the mainline Linux Kernel and HAVEGED are using the same concept to generate the entropy (utilizing the CPU jitter) the implementation is completely different. In this sense, HAVEGED can be viewed as another entropy source.