如何安装 pandom ： 一个针对 Linux 的真随机数生成器
随机数 pandom
![](/data/attachment/album/201705/17/204255id9jk0uijgo0g6jk.jpg)


本教程只针对 amd64/x86\_64 架构 Linux 内核版本大于等于 2.6.9 的系统。本文将解释如何安装 [pandom](http://ncomputers.org/pandom)，这是一个由 ncomputers.org 维护的定时抖动真随机数生成器。


### 简介


在现在的计算机状况下，比如说配置了固态硬盘（SSD）的个人电脑和虚拟专用服务器（VPS）的环境中，Linux 内核内置的真随机数发生器提供的吞吐量很低。


而出于各种不同的加密目的使得对真随机数的需求持续增长，从而使得这个低吞吐量问题在 Linux 实现中变得越来越严重。


在与上述相同的物理或者虚拟环境下，并假设没有其它进程以 root 身份向 `/dev/random` 进行写操作的话，64 [ubits](http://ncomputers.org/ubit)/64 bits 的 pandom 可以以 8 KiB/s 的速率生成随机数。


### 1 pandom 的安装


#### 1.1 获得 root 权限


Pandom 必须以 root 身份来安装，所以在必要的时候请运行如下命令：



```
su -

```

#### 1.2 安装编译所需的依赖


为了下载并安装 pandom，你需要 GNU `as` 汇编器、GNU `make`、GNU `tar` 和 GNU `wget` (最后两个工具通常已被安装)。随后你可以按照你的意愿卸载它们。


**基于 Arch 的系统：**



```
pacman -S binutils make

```

**基于 Debian 的系统：**



```
apt-get install binutils make

```

基于 Red Hat 的系统：



```
dnf install binutils make
yum install binutils make

```

**基于 SUSE 的系统：**



```
zypper install binutils make

```

#### 1.3 下载并析出源码


下面的命令将使用 `wget` 和 `tar` 从 ncomputers.org 下载 pandom 的源代码并将它们解压出来：



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

```

#### 1.4 在安装前进行测试 (推荐)


这个被推荐的测试将花费大约 8 分钟的时间，它将检查内核支持情况并生成一个名为 `checkme` 的文件（在下一节中将被分析）。



```
make check

```

#### 1.5 确定系统的初始化程序


在安装 pandom 之前，你需要知道你的系统使用的是哪个初始化程序。假如下面命令的输出中包含 `running`，则意味着你的系统使用了 `systemd`，否则你的系统则可能使用了一个 `init.d` 的实现（例如 upstart、sysvinit）。



```
systemctl is-system-running
running

```

#### 1.6 安装 pandom


一旦你知道了你的系统使用何种 Linux 实现，那么你就可以相应地安装 pandom 了。


**使用基于 init.d 作为初始化程序（如： upstart、sysvinit）的系统：**


假如你的系统使用了一个 init.d 的实现（如： upstart、sysvinit），请运行下面的命令来安装 pandom：



```
make install-init.d

```

**以 systemd 作为初始化程序的系统：**


假如你的系统使用 `systemd`，则请运行以下命令来安装 pandom：



```
make install-systemd

```

### 2 checkme 文件的分析


在使用 pandom 进行加密之前，强烈建议分析一下先前在安装过程中生成的 `checkme` 文件。通过分析我们便可以知道用 pandom 生成的数是否真的随机。本节将解释如何使用 ncomputers.org 的 shell 脚本 `entropyarray` 来测试由 pandom 产生的输出的熵及序列相关性。


**注**：整个分析过程也可以在另一台电脑上完成，例如在一个笔记本电脑或台式机上。举个例子：假如你正在一个资源受到限制的 VPS 上安装 pandom 程序，或许你更倾向于将 `checkme` 复制到自己的个人电脑中，然后再进行分析。


#### 2.1 获取 root 权限


`entropyarray` 程序也必须以 root 身份来安装，所以在必要时请运行如下命令：



```
su -

```

#### 2.2 安装编译所需的依赖


为了下载并安装 `entropyarray`， 你需要 GNU g++ 编译器、GNU `make`、GNU `tar` 和 GNU `wget`。在随后你可以任意卸载这些依赖。


**基于 Arch 的系统：**



```
pacman -S gcc make

```

**基于 Debian 的系统：**



```
apt-get install g++ make

```

**基于 Red Hat 的系统：**



```
dnf install gcc-c++ make
yum install gcc-c++ make

```

**基于 SUSE 的系统：**



```
zypper install gcc-c++ make

```

#### 2.3 下载并析出源码


以下命令将使用 `wget` 和 `tar` 从 ncomputers.org 下载到 entropyarray 的源码并进行解压：



```
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 安装 entropyarray


**注**：如果在编译过程中报有关 `-std=c++11` 的错误，则说明当前系统安装的 GNU g++ 版本不支持 ISO C++ 2011 标准，那么你可能需要在另一个支持该标准的系统中编译 ncomputers.org/entropy 和 ncomputers.org/rearray （例如在一个你喜爱的较新的 Linux 发行版本中来编译）。接着使用 `make install` 来安装编译好的二进制文件，再接着你可能想继续运行 `entropyarray` 程序，或者跳过运行该程序这一步骤，然而我还是建议在使用 pandom 来达到加密目地之前先分析一下 `checkme` 文件。



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

```

#### 2.5 分析 checkme 文件


**注**：64 [ubits](http://ncomputers.org/ubit) / 64 bits 的 pandom 实现所生成的结果中熵应该高于 `15.977` 且 `max` 字段低于 `70`。假如你的结果与之相差巨大，或许你应该按照下面第 5 节介绍的那样增加你的 pandom 实现的不可预测性。假如你跳过了生成 `checkme` 文件的那一步，你也可以使用其他的工具来进行测试，例如 [伪随机数序列测试](http://www.fourmilab.ch/random/)。



```
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 卸载 entropyarray (可选)


假如你打算不再使用 `entropyarray`，那么你可以按照你自己的需求卸载它：



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

```

### 3 使用 debian 的软件仓库来进行安装


假如你想在你基于 debian 的系统中让 pandom 保持更新，则你可以使用 ncomputers.org 的 debian 软件仓库来安装或者重新安装它。


#### 3.1 获取 root 权限


以下的 debian 软件包必须以 root 身份来安装，所以在必要时请运行下面这个命令：



```
su -

```

#### 3.2 安装密钥


下面的 debian 软件包中包含 ncomputers.org debian 软件仓库的公匙密钥：



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

```

#### 3.3 安装软件源列表


下面这些 debian 软件包含有 ncomputers.org debian 软件仓库的软件源列表，这些软件源列表对应最新的 debian 发行版本(截至 2017 年)。


**注**：你也可以将下面的以 `#` 注释的行加入 `/etc/apt/sources.list` 文件中，而不是为你的 debian 发行版本安装对应的 debian 软件包。但假如这些源在将来改变了，你就需要手动更新它们。


**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 升级软件源列表


一旦密钥和软件源列表安装完成，则可以使用下面的命令来更新：



```
apt-get update

```

#### 3.5 测试 pandom


测试完毕后，你可以随意卸载下面的软件包。


**注**：假如你已经在你的 Linux 中测试了 pandom ， 则你可以跳过这一步。



```
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 安装 pandom



```
apt-get install pandom

```

### 4 管理 pandom


在 pandom 安装完成后，你可能想对它进行管理。


#### 4.1 性能测试


pandom 提供大约 8 kB/s 的随机数生成速率，但它的性能可能根据环境而有所差异。



```
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 熵和序列相关性检验


除了 ncomputers.org/entropyarray，还存在更多的测试，例如 [Ilja Gerhardt 的 NIST 测试套件](https://gerhardt.ch/random.php)。



```
entropyarray /dev/random 1M

```

#### 4.3 系统服务


pandom 还可以以系统服务的形式运行。


**基于 init.d 的初始化系统（如 upstart、sysvinit）：**



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

```

**以 systemd 作为初始化程序的系统：**



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

```

### 5 增强不可预测性或者性能


假如你想增加你编译的 pandom 程序的不可预测性或者性能，你可以尝试增加或删减 CPU 时间测量选项。


#### 5.1 编辑源文件


请按照自己的意愿，在源文件 `test.s` 和 `tRNG.s` 中增加或者移除 `measurement blocks` 字段。



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

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

```

#### 5.2 测试不可预测性


我们总是建议在使用个人定制的 pandom 实现来用于加密目地之前，先进行一些测试。



```
make check

```

#### 5.3 安装定制的 pandom


假如你对测试的结果很满意，你就可以使用下面的命令来安装你的 pandom 实现。



```
make install

```

更多额外信息及更新详见 <http://ncomputers.org/pandom> 。


（题图：Pixabay，CC0）




---


via: <https://www.howtoforge.com/tutorial/how-to-install-pandom-a-true-random-number-generator/>


作者：[Oliver](https://www.howtoforge.com/tutorial/how-to-install-pandom-a-true-random-number-generator/) 译者：[FSSlc](https://github.com/FSSlc) 校对：[wxy](https://github.com/wxy)


本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出


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

### On this page

[Introduction](#introduction)[1 Installation of pandom](#-installation-of-pandom)[1.1 Gain root access](#-gain-root-access)[1.2 Install build dependencies](#-install-build-dependencies)[Arch based systems](#arch-based-systems)[Debian based systems](#debian-based-systems)[Red Hat based systems](#red-hat-based-systems)[SUSE based systems](#suse-based-systems)[1.3 Download and extract sources](#-download-and-extract-sources)[1.4 Test before installing (recommended)](#-test-before-installing-recommended)[1.5 Determine init system](#-determine-init-system)[1.6 Install pandom](#-install-pandom)[init.d based init system (e.g: upstart, sysvinit)](#initd-based-init-system-eg-upstart-sysvinit)[systemd as init system](#systemd-as-init-system)

[2 Analysis of checkme file](#-analysis-of-checkme-file)[3 Installation using debian repository](#-installation-using-debian-repository)[4 Managing pandom](#-managing-pandom)[5 Increasing unpredictability or performance](#-increasing-unpredictability-or-performance)

This tutorial is for amd64 / x86_64 linux kernel versions greater and equal to 2.6.9. It explains how to install [pandom](http://ncomputers.org/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](http://ncomputers.org/ubit) / 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 **as**sembler, 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](http://unix.stackexchange.com/a/18210/94448) 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](http://ncomputers.org/ubit) / 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](http://www.fourmilab.ch/random/).

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](https://gerhardt.ch/random.php).

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](http://ncomputers.org/pandom)