haveged

A Linux entropy source using the HAVEGE algorithm Haveged is a user space entropy daemon which is not dependent upon the standard mechanisms for harvesting randomness for the system entropy pool. This is important in systems with high entropy needs or limited user interaction (e.g. headless servers). Haveged uses HAVEGE (HArdware Volatile Entropy Gathering and Expansion) to maintain a 1M pool of random bytes used to fill /dev/random whenever the supply of random bits in /dev/random falls below the low water mark of the device. The principle inputs to haveged are the sizes of the processor instruction and data caches used to setup the HAVEGE collector. The haveged default is a 4kb data cache and a 16kb instruction cache. On machines with a cpuid instruction, haveged will attempt to select appropriate values from internal tables.