Steven Kirkland lemonforest

Two Fast Methods of Generating True Random Numbers on the Arduino

Arduino true random number generator

B. Peng

December 2017

Abstract

The AVR series microcontrollers are a collection of cheap and versatile chips that are used in many applications ranging from hobbist projects to commercial infrastructure. One major problem for some hobbists is the lack of secure random number generation on the Arduino platform. The included pseudo-random number generator (PRNG) is very easy to defeat and is useless for any crypto-related uses. One recommendation from the Arduino Reference Manual is to use atmospheric noise from the chip's analog sensor pins as seed data^[6].
Unfortunately this method is extremely weak and should not be used to emulate a true random number generator (TRNG). Existing methods such as using the internal timer drift or using a dedicated generator are either too slow, requires extensive external hardware or modifications to the microcontroller's internal mech

introduction

I wanted to replace rsync for my current host backups.

I had 2 hosts (1 laptop and 1 desktop) that would get there changes polled from a backup server. (polled = cronjob ran every hours) Ofcourse those boxes are not always on and a frenzy of cron mails happen every now and then.

I replaced everything with syncthing, they have clients available for linux, illumos, openbsd and mac. With the config below (client::folder master = yes, server::folder master = no) we prevent the server from accidentally overriding a file on the client. The client knows the server's IPv4 and/or IPv6 address so we do not need global or local discovery nor UPnP.

Compile and run

gcc adt.c array.c -o adt
./adt

FreeNAS

I started using FreeNAS in August 2013. It is fantastic piece of software and I have been really impressed by the upgrades just in the few months I've been using it. It looks like they recently went to a plugin system as of version 9 to make installing software easier for end users. I've ran into several issues related to plugins and user + group permissions so I decided to just use the available FreeBSD port system. After fiddling for a few days (now turned into months) I believe I have created something helpful for the community and anyone interested in picking up the port system. The sandbox nature of FreeNAS's jail system is especially helpful for playing around without having any consequence on your core system.

Here are straight-forward instructions to setting up a bunch of different software on FreeNAS. If you make a terrible error, just throw up another plugin sandbox and repeat.

	##########
	# Win10 Initial Setup Script
	# Author: Disassembler <[email protected]>
	# Version: 1.7, 2016-08-15

	# dasm's script: https://github.com/Disassembler0/Win10-Initial-Setup-Script/

	# THIS IS A PERSONALIZED VERSION
	# This script leaves more MS defaults on, including MS security features.
	# Tweaked based on personal preferences for @alirobe 2016-11-16 - v1.7.1

	/* Read this comment first: https://gist.github.com/tonious/1377667#gistcomment-2277101
	* 2017-12-05
	*
	* -- T.
	*/

	#define _XOPEN_SOURCE 500 /* Enable certain library functions (strdup) on linux. See feature_test_macros(7) */

	#include <stdlib.h>
	#include <stdio.h>