The infnoise application reads random data from the Infinite Noise USB key and writes
binary data to stdout. To complile it in Linux, make sure you have the libftdi-dev
package installed, and just type "make".
To run the infnoise application, make sure the Infinite Noise USB stick is
plugged in, and from a shell, type:
sudo ./infnoise > randbytes
This will fill the file randbytes with random data endlessly, so hit Ctrl+C to kill it
after a while. If all you want to do is verify the output using the dieharder tests, you
can use:
sudo ./infnoise | dieharder -g 200 -a
The Infinite Noise USB driver uses the open source FTDI driver documented at:
http://www.intra2net.com/en/developer/libftdi/documentation/group__libftdi.html
This talks to the FT240X USB 2.0 interface chip on the USB stick. It uses "bitbang" mode
to drive the clock signals of the Infinite Noise Multiplier, and receives one random bit
of output per byte written to the device. These bits are collected into bytes, and sent
through a "health checker", which verifies that the bits look basically like INM output,
with about the expected level of entropy.
If the measured level of entropy deviates from the theoretical value by more than 5%, then
the infnoise application exits with an error message. If this happens, you can see the
raw data from the INM for yourself by running
sudo infnoise --raw > randbytes
Kill it after a while, and check it out with with a program like hexdump. In general,
there should be random 0's and 1's, and no more than 5 1's or 0's in a row. When the
health checker sees long strings of 0's or 1's, it exits.
