timer_entropyd feeds the /dev/random device with entropy data (random values) read from timers. It does this by measuring how much longer or shorter a sleep takes, since this fluctuates by a few microseconds every time. The time for a sleep jitters due to the fact that the frequency of the clocks of the timers change when they become colder or hotter. This program does not require any extra hardware. It produces around 500 bits per second. This program is also usable with virtualized systems.
Entropy Broker is an infrastructure for distributing cryptographically secure random numbers (entropy data) from one or more servers to one or more clients. This prevents /dev/random from ever becoming empty. This is useful, for example, for virtual machines which naturally have no source of randomness.