julescarbon

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

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

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

	// munged from https://github.com/simontime/Resead

	namespace sead
	{
	class Random
	{

	### JHW 2018
	import numpy as np
	import umap



	# This code from the excellent module at:
	# https://stackoverflow.com/questions/4643647/fast-prime-factorization-module

	import random

	@binkmail.com
	@bobmail.info
	@chammy.info
	@devnullmail.com
	@letthemeatspam.com
	@mailinater.com
	@mailinator.net
	@mailinator2.com
	@notmailinator.com
	@reallymymail.com

	<!doctype html>
	<html>
	<title>Flatten.js, General SVG Flattener</title>

	<head>
	<script>
	/*
	Random path and shape generator, flattener test base: https://jsfiddle.net/fjm9423q/embedded/result/
	Basic usage example: https://jsfiddle.net/nrjvmqur/embedded/result/

	# Tell system when Xcode utilities live:
	sudo xcode-select -switch /Applications/Xcode.app/Contents/Developer

	# Set "opendiff" as the default mergetool globally:
	git config --global merge.tool opendiff

	require "rubygems"
	require "twitter"
	require "json"

	# things you must configure
	TWITTER_USER = "your_username"
	MAX_AGE_IN_DAYS = 1 # anything older than this is deleted

	# get these from dev.twitter.com
	CONSUMER_KEY = "your_consumer_key"

	#!/usr/bin/env perl

	use strict;
	use warnings;

	use WWW::Tumblr;

	die 'u need to specify some filesz' if not @ARGV;

	my $t = WWW::Tumblr->new(