RNG Tools

Using Qrypt’s Quantum Entropy in RNG Tools

rng-tools is a utility that allows you to inject entropy from hardware sources, prngs, and http streams into system devices. Qrypt’s Quantum Entropy service is a random source option in rng-tools, allowing you to inject quantum entropy into system devices such as ‘/dev/random’, ‘/dev/urandom’, and user-defined nodes or files.

This service requires an access token. Follow the steps in Getting Started to obtain an access token.

More information about rng-tools can be found on the rng-tools Github and the rng-tools wiki page.


To use Qrypt’s Quantum Entropy service in rng-tools, rng-tools must be installed and configured.

Clone the latest rng-tools master from GitHub.

git clone https://github.com/nhorman/rng-tools

Install rng-tools dependencies. Additional packages may be required, depending on linux distro. The configure script below will name any missing packages it encounters.

sudo apt install \
    make \
    libtool \
    libxml2-dev \
    libssl-dev \
    libcurl3-dev \
    libp11-dev \
    librtlsdr-dev \
    libusb-1.0-0-dev \
    libjansson-dev \

Add --disable-dependency-tracking to the ‘./configure’ command if needed.

sudo make install

Verify installation.

which rngd

Command Line Usage

The resulting ‘rngd’ executable can run directly to start either a daemon or a foreground process. By default, ‘rngd’ will run as a background daemon and attempt to use the ‘hwrng’, ’errand’, ‘pkcs11’, and ‘rtlsdr’ random sources.

To run ‘rngd’ using exclusively Qrypt’s Quantum Entropy, run the following command. This will run ‘rngd’ as a foreground process with the Qrypt source enabled and all other entropy sources disabled. ‘rngd’ will send its random to the /dev/random device.

Note that ‘sudo’ is needed in the command because ‘rngd’ accesses the root folder.

sudo rngd -f -x hwrng -x rdrand -x pkcs11 -x rtlsdr -n qrypt -O qrypt:tokenfile:<qrypt token path>

Command line options:

Option Description
-f Run 'rngd' as a foreground process. If omitted, 'rngd' will run as a background daemon.
-o <path> Device or file for the random number output. Defaults to '/dev/random'.
-x <source> Disables the specified source. For example, '-x hwrng'.
-n <source> Enables the specified source. For example, '-n qrypt'.
-O <source>:<key>:<value> Sets a source specific configuration option. For example, '-O qrypt:tokenfile:/etc/rngd/qrypt.token'.

Service Usage

rng-tools comes with a ‘rngd.service’ file for setting up a systemd service. To configure rngd to automatically start the Qrypt source on boot, follow these steps:

Save your Qrypt api token to a system-accessible directory, such as ‘/etc/rngd/qrypt.token’. Then, edit ‘rngd.service’ to add Qrypt arguments and options.

Note that ‘sudo’ is needed in the subsequent commands because ‘rngd’ accesses the root folder.

Description=Hardware RNG Entropy Gatherer Daemon

# The '-f' option is required for the systemd service 'rngd' to work with Type=simple
ExecStart=<rngd install path> -f -x hwrng -x rdrand -x pkcs11 -x rtlsdr -n qrypt -O qrypt:tokenfile:<qrypt token path>


Copy the ‘rngd’ service to systemd.

sudo cp rngd.service /etc/systemd/system/rngd.service
sudo chmod 644 /etc/systemd/system/rngd.service

Start the ‘rngd’ service.

sudo systemctl daemon-reload
sudo systemctl start rngd

Verify the ‘rngd’ service is running properly.

sudo systemctl status rngd

Enable the ‘rngd’ service for it to start on system boot.

sudo systemctl enable rngd