In Linux, sometimes you may need to generate some entropy.
There are both hardware and software solutions:
- Hardware solutions: they can generate more entropy per second, but you need physical access
- Software solutions: they have less performance, but you just need
rootpermissions (no physical access)
Typically it’s a USB device that generates and streams some random numbers.
One of such devices is TrueRNG (price is approx: 50$).
This program feeds random data from hardware device to kernel.
rngd -r "/dev/urandom"
Here we have used
rngd program (man 8 rngd for more details).
This daemon feeds data from a random number generator to the kernel’s random number entropy pool, after first checking the data to ensure that it is properly random.
Audio Entropy Daemon
This program feeds the
/dev/random device with entropy-data read from an audio device.
The audio-data is not copied as is but first de-biased and analysed to determine how much bits of entropy is in it.
The official website of the program is here.