rtl2832-entropyd

rtl2832_entropyd is a program that is designed to feed entropy into the linux /dev/random kernel entropy pool. It automatically forks and runs as a daemon, unless one of the testing options, -o or -t, are selected. Then it never forks.

To use it, you need an rtl2832 USB dongle. They are relatively cheap (< $10 on ebay), and are actually used to listen to a broad range of radio transmissions. This application exploits the radio noise in the atmosphere to extract entropy. The kernel already has a module to use the rtl2832 for its intended purpose, listening to radio, so if you want to use it to generate entropy, you will have to blacklist that module, so it doesn't load. If it is loaded, this program will not be able to acquire the rtl2832 device, and won't run. Create the file /etc/modprobe.d/blacklist-dvb_usb_rtl28xxu.conf with the line blacklist dvb_usb_rtl28xxu in it.

The project website is an html version of the man page, so you can find more complete information there.