1. Introduction

Random numbers and random number generators play a crucial role in the modern world. True random numbers are required in a variety of domains varying from the ethernet ports of our computers to betting houses across the globe. Achieving non-predictable true randomness is a difficult problem to solve. The Peerplays blockchain has managed to develop a true random number generator as one of the offshoots of the blockchain technology. The provably fair RNG algorithm ensures the following characteristics.

1. Not predictable

2. Verifiable

3. Non-disputable

In addition to that, the Peerplays blockchain RNG has a uniform probability distribution characteristic, which is what is sort in most of the cases.

2. Building RNG Server on Ubuntu 18.04 LTS and Installation Instructions

System Requirements

The following table lists what should be considered the minimum system requirements for running a witness node:

These requirements are, as of the time of writing, so consider deploying a server with specs slightly higher than the ones listed above in order to "future proof" your server in case the minimum requirements grow in the future.

Dependencies

The following dependencies are necessary for a clean install of Ubuntu 18.04 LTS and install them with the following command.

sudo apt-get -y install gcc g++ cmake make libbz2-dev libdb++-dev libdb-dev libssl-dev openssl libreadline-dev autoconf libtool git libcurl4-openssl-dev

Build Boost 1.67.0

mkdir $HOME/src
cd $HOME/src
export BOOST_ROOT=$HOME/src/boost_1_67_0
sudo apt-get update
sudo apt-get install -y autotools-dev build-essential  libbz2-dev libicu-dev python-dev
wget -c 'http://sourceforge.net/projects/boost/files/boost/1.67.0/boost_1_67_0.tar.bz2/download' -O boost_1_67_0.tar.bz2
tar xjf boost_1_67_0.tar.bz2
cd boost_1_67_0/
./bootstrap.sh "--prefix=$BOOST_ROOT"
./b2 install

Building Peerplays RNG Server

cd $HOME/src
export BOOST_ROOT=$HOME/src/boost_1_67_0
git clone https://github.com/peerplays-network/peerplays.git
cd peerplays
git checkout feature/rng
git submodule update --init --recursive
git submodule sync --recursive
cmake -DBOOST_ROOT="$BOOST_ROOT" -DCMAKE_BUILD_TYPE=Release
make -j$(nproc)

sudo make install # this can install the executable files under /usr/local
# Input passwrod upon need

Starting the Peerplays Witness Node

If we have installed the blockchain following the above steps, the node can be started as follows:

witness_node 
# If you need the logs, the following can be helpful
# witness_node 2>&1 peerplays.log

Launching the Witness creates the required directories.

Next, stop the witness node before continuing and make the following changes in the config.ini file.

To stop the witness use ctrl + c

$ vi witness_node_data_dir/config.ini
p2p-endpoint = 0.0.0.0:9777
seed-node = [""]
rpc-endpoint = 0.0.0.0:8090
genesis-json = genesis.json
enable-stale-production = true
required-participation = false

Leave other lines to the defaults.

Start the Witness node again.

witness_node

The Random Number Generator is running and exposed through the port 8090 now. You may skip the following witness as a service for the time being and test the RNG. For testing RNG, skip to the API specifications section. Once RNG is found working, come back and set the witness as a service and make changes necessary to run it on startup as given below.

Starting the witness as a service

We can add the peerplays blockchain node as a service using the following steps.

under, /etc/systemd/system create a file with the following content. It’s assumed that “ubuntu” is the name of your home folder. If not replace with proper home folder name judiciously.

[Unit]
Description=Witness
[Service]
User=ubuntu
WorkingDirectory=/home/ubuntu
ExecStart=/home/ubuntu/witness_node
Restart=always
[Install]
WantedBy=mult-user.target

Auto-Starting the Witness Node

It's important for your Witness node to start when your system boots up. The filepaths here assume that you installed your witness into /home/ubuntu

Step 1. Create a log file to hold your stdout/err logging

sudo touch /var/log/peerplays.log

Step 2. Save this file in your Peerplays directory. vi /home/ubuntu/start.sh

#!/bin/bash

cd /home/ubuntu
witness_node &> /var/log/peerplays.log

Step 3. Make it executable

chmod 744 /home/ubuntu/start.sh

Step 4. Create this file: sudo vi /etc/systemd/system/peerplays.service

Note: Check the path for start.sh, if necessary, change it to match where your start.sh file actually is.

[Unit]
Description=Peerplays Witness
After=network.target

[Service]
ExecStart=/home/ubuntu/start.sh

[Install]
WantedBy = multi-user.target

Step 5. Enable the service

sudo systemctl enable peerplays.service

Important: Make sure you don't get any errors.

sudo systemctl status peerplays.service

Step 6. Stop your Witness node, if it's currently running, then start it with the service.

sudo systemctl start peerplays.service

Step 7. Check your logfile for entries

tail -f /var/log/peerplays.log

3. API Specifications

The API is exposed at the URL: HTTP://<IP of the RNG server>:8090/ws. The API supports post request method over HTTP for generating and fetching random numbers from the blockchain. The parameters of the post method are

method: post
data:
{
"method": "call", "params": [
    "database",     "get_random_number_ex",     [<min>, <max>, <count>, <repeat>]
    ], "jsonrpc": "2.0", "id": 1
}

Where

min: Lowest number in the random sequence, lower permitted value is 0 max: Highest number in the random sequence will be max - 1 count: Number of random numbers to be pulled, the maximum permitted limit is 100,000. repeat: true/false Can there be repetition in the random numbers pulled? “true” means numbers are repeated and “false” means numbers are not repeated.

And it returns

{"id":1,"jsonrpc":"2.0","result":[<count number of values comma separated>]}

The result, random numbers are under the key “result”.

Examples

Curl

curl --data '{"method": "call", "params": ["database", "get_random_number_ex", [1, 10, 4, false]], "jsonrpc": "2.0", "id": 1}' http://charlie.peerplays.download/api

Which returns

{"id":1,"jsonrpc":"2.0","result":[3,1,9,6]}

Node.js

var request = require('request');
var dataString = '{"method": "call", "params": ["database", "get_random_number_ex", [1, 10, 4, false]], "jsonrpc": "2.0", "id": 1}';
var options = {    url: 'http://charlie.peerplays.download/api',    method: 'POST',    body: dataString};
function callback(error, response, body) {    if (!error && response.statusCode == 200) {        console.log(body);    }}
request(options, callback);

Python

import requests
data = '{"method": "call", "params": ["database", "get_random_number_ex", [1, 10, 4, false]], "jsonrpc": "2.0", "id": 1}'
response = requests.post('http://charlie.peerplays.download/api', data=data)

PHP

<?phpinclude('vendor/rmccue/requests/library/Requests.php');Requests::register_autoloader();$headers = array();$data = '{"method": "call", "params": ["database", "get_random_number_ex", [1, 10, 4, false]], "jsonrpc": "2.0", "id": 1}';$response = Requests::post('http://charlie.peerplays.download/api', $headers, $data);

Go-LANG

package main
import ( "fmt" "io/ioutil" "log" "net/http")
func main() { client := &http.Client{} var data = []byte(`{{"method": "call", "params": ["database", "get_random_number_ex", [1, 10, 4, false]], "jsonrpc": "2.0", "id": 1}}`) req, err := http.NewRequest("POST", "http://charlie.peerplays.download/api", data) if err != nil { log.Fatal(err) } resp, err := client.Do(req) if err != nil { log.Fatal(err) } bodyText, err := ioutil.ReadAll(resp.Body) if err != nil { log.Fatal(err) } fmt.Printf("%s\n", bodyText)}