How to install pandom: a true random number generator for Linux

This tutorial is for amd64 / x86_64 linux kernel versions greater and equal to 2.6.9. It explains how to install pandom: a timing jitter true random number generator maintained by ncomputers.org

Introduction

The built-in Linux kernel true random number generator provides low throughput under modern circumstances, as for example: personal computers with solid state drives (SSD) and virtual private servers (VPS).

This problem is becoming popular in linux implementations, because of the continuously increasing need for true random numbers, mainly by diverse cryptographic purposes.

Pandom outputs around 8 KiB/s entropy of 64 ubits / 64 bits, is compatible with physical and virtual environments and assumes, that no other process running as root user writes to /dev/random.

1 Installation of pandom

1.1 Gain root access

Pandom must be installed as root, run this command if needed.

su -

1.2 Install build dependencies

In order to download and install pandom, you need: GNU assembler, GNU make, GNU tar and GNU wget (the last two usually installed already). You may uninstall them later at will.

Arch based systems

pacman -S binutils make

Debian based systems

apt-get install binutils make

Red Hat based systems

dnf install binutils make

yum install binutils make

SUSE based systems

zypper install binutils make

1.3 Download and extract sources

These commands download and extract the sources of pandom from ncomputers.org using wget and tar.

wget http://ncomputers.org/pandom.tar.gz
tar xf pandom.tar.gz
cd pandom/amd64-linux

1.4 Test before installing (recommended)

This recommended test takes around 8 minutes. It checks for kernel support and generates a file named checkme (analyzed on the next section).

make check

1.5 Determine init system

Before installing pandom, you need to know, which init software does your system use. If the following command outputs the word running, it means that your system is using systemd, otherwise it is likely, that your system is using an init.d implementation (e.g: upstart, sysvinit). There might be some exceptions, more information in these unix.stackexchange.com answers.

systemctl is-system-running

running

1.6 Install pandom

Once you know which system does your linux implementation use, then you may install pandom accordingly.

init.d based init system (e.g: upstart, sysvinit)

Install pandom running this command, if your system is using an init.d implementation (e.g: upstart, sysvinit).

make install-init.d

systemd as init system

Install pandom running this command, if your system is using systemd.

make install-systemd

2 Analysis of checkme file

Before using pandom for cryptographic purposes, it is highly recommended to analyze checkme file generated during the installation process in the previous section of this tutorial. This task is useful for knowing if the numbers are truly random or not. This section explains how to analyze checkme file using ncomputers.org/entropyarray: a shell script, that tests entropy and serial correlation of its input.

Note: this analysis might be run in another computer, such as a laptop or desktop computer. For example: if you are installing pandom in a constrained-resources virtual private server (VPS), you might opt to copy checkme file to your personal computer, in order to analyze it there.
You may also use Entropy Online Tester.

2.1 Gain root access

Entropyarray must be installed as root, run this command if needed.

su -

2.2 Install build dependencies

In order to download and install entropyarray, you need: GNU g++ compiler, GNU make, GNU tar and GNU wget (the last two usually installed already). You may uninstall them later at will.

Arch based systems

pacman -S gcc make

Debian based systems

apt-get install g++ make

Red Hat based systems

dnf install gcc-c++ make

yum install gcc-c++ make

SUSE based systems

zypper install gcc-c++ make

2.3 Download and extract sources

These commands download and extract the sources of entropyarray from ncomputers.org using wget and tar.

wget http://ncomputers.org/rearray.tar.gz
wget http://ncomputers.org/entropy.tar.gz
wget http://ncomputers.org/entropyarray.tar.gz

tar xf entropy.tar.gz
tar xf rearray.tar.gz
tar xf entropyarray.tar.gz

2.4 Install entropyarray

Note: errors regarding -std=c++11 mean that the GNU g++ compiler version doesn't support ISO C++ 2011 standard. You may try to compile ncomputers.org/entropy and ncomputers.org/rearray in another system that supports it (e.g: GNU g++ in a newer version of your favorite linux distribution) and then install the compiled binaries using make install in the system you would like to run entropyarray, or skip this step, despite it is highly recommended that you analyze checkme file before using pandom for any cryptographic purpose.

cd rearray; make install; cd ..
cd entropy; make install; cd ..
cd entropyarray; make install; cd ..

2.5 Analyze checkme file

Note: 64 ubits / 64 bits pandom implementations should result this test with entropy above 15.977 and max frequency below 70. If your results differ too much, you may try to increase the unpredictability of your pandom implementation as described in the fifth section of this tutorial. In case you skipped the last step, you may use other tools such as pseudorandom number sequence test.

entropyarray checkme

entropyarray in /tmp/tmp.mbCopmzqsg
15.977339
min:12
med:32
max:56
15.977368
min:11
med:32
max:58
15.977489
min:11
med:32
max:59
15.977077
min:12
med:32
max:60
15.977439
min:8
med:32
max:59
15.977374
min:13
med:32
max:60
15.977312
min:12
med:32
max:67

2.6 Uninstall entropyarray (optional)

If you plan to not use entropyarray any more, then you might want to uninstall it at will.

cd entropyarray; make uninstall; cd ..
cd entropy; make uninstall; cd ..
cd rearray; make uninstall; cd ..

3 Installation using debian repository

If you would like to keep pandom updated on your debian based system, you may opt to install / reinstall it using ncomputers.org debian repository.

3.1 Gain root access

The below debian packages must be installed as root, run this command if needed.

su -

3.2 Install keyring

This debian package includes the public key of the ncomputers.org debian repository.

wget http://ncomputers.org/debian/keyring.deb
dpkg -i keyring.deb
rm keyring.deb

3.3 Install sources list

These debian packages include the sources list of the ncomputers.org debian repository according to the latest debian distributions (year 2017).

Note: It is also possible to write the commented lines below in /etc/apt/sources.list, instead of installing the respective debian package for your debian distribution, but if these sources change in the future, then you would need to update them manually.

Wheezy

#deb http://ncomputers.org/debian wheezy main
wget http://ncomputers.org/debian/wheezy.deb
dpkg -i wheezy.deb
rm wheezy.deb

Jessie

#deb http://ncomputers.org/debian jessie main
wget http://ncomputers.org/debian/jessie.deb
dpkg -i jessie.deb
rm jessie.deb

Stretch

#deb http://ncomputers.org/debian stretch main
wget http://ncomputers.org/debian/stretch.deb
dpkg -i stretch.deb
rm stretch.deb

3.4 Update sources list

Once the keyring and sources list are installed.

apt-get update

3.5 Test pandom

Once tested, you may uninstall the below package at will.

Note: if you have already tested pandom in your linux implementation, you may skip this step.

apt-get install pandom-test
pandom-test

generating checkme file, please wait around 8 minutes ...
entropyarray in /tmp/tmp.5SkiYsYG3h
15.977366
min:12
med:32
max:57
15.977367
min:13
med:32
max:57
15.977328
min:12
med:32
max:61
15.977431
min:12
med:32
max:59
15.977437
min:11
med:32
max:57
15.977298
min:11
med:32
max:59
15.977196
min:10
med:32
max:57

3.6 Install pandom

apt-get install pandom

4 Managing pandom

After pandom was installed, you might want to manage it.

4.1 Performance test

Pandom offers around 8 kilobytes per second, but its performance may vary depending on the environment.

dd if=/dev/random of=/dev/null bs=8 count=512

512+0 records in
512+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.451253 s, 9.1 kB/s

4.2 Entropy and serial correlation test

Besides of ncomputers.org/entropyarray, there are more tests, for example NIST testsuite by Ilja Gerhardt.

entropyarray /dev/random 1M

4.3 System service

Pandom runs as a system service.

init.d based init system (e.g: upstart, sysvinit)

/etc/init.d/random status
/etc/init.d/random start
/etc/init.d/random stop
/etc/init.d/random restart

systemd as init system

systemctl status random
systemctl start random
systemctl stop random
systemctl restart random

5 Increasing unpredictability or performance

If you would like to try to increase the unpredictabiity or the performance of your pandom implementation, you may try to add or delete CPU time measurements.

5.1 Edit source files

In the source files test.s and tRNG.s add or remove measurement blocks at will.

#measurement block
mov $35,%rax
syscall
rdtsc
[...]

#measurement block
mov $35,%rax
syscall
rdtsc
[...]

5.2 Test the unpredictability

We recommend to always test any personalized pandom implementation before using it for cryptographic purposes.

make check

5.3 Install personalized pandom

If you are happy with the results, then you may install your personalized pandom implementation.

make install

Additional information and updates: http://ncomputers.org/pandom