Jonathan Duke jonathanduke

VPN Bridge Setup: DD-WRT to Asus (Merlin)

I needed to create a VPN bridge from my network, which has a public IP, to an internal network, which is behind CGNAT and does not have a routable IP. The routers involved were an R6700v3 running DD-WRT and an RT-N66U running the Merlin 380.70 firmware, but the firewall rules should apply for any similar router. While this is not a comprehensive guide, I needed to record the details of the custom steps here in case I have to set up something similar in the future.

1. OpenVPN Setup

Setting up an OpenVPN server on the DD-WRT side and connecting it to the Asus is mostly straightforward using the GUI, but some manual steps were required. I did notice that the Asus had some issues with a few of the OpenVPN parameters, and it had trouble connecting in TCP mode, so I used UDP.

To set up OpenVPN with TLS authentication and X.509 certificates, I used Easy-RSA to generate a certificate authority and required certs:

Deferred Proof of Authorship using Digital Signatures and Blockchain Timestamps

by Jonathan Duke

Abstract. Suppose an author has created a document that he wants to publish anonymously, but at some point in the future he would like to have the option to prove both his identity and the time of creation. A digital signature can be used to sign the document's content, but there is no mechanism to prevent another person from spoofing the timestamp and signing their own version of the document to claim they are the original author. Using a public, permanent blockchain such as bitcoin could allow the author to augment the digital signature with a timestamp that could be proven to match the document signature. The signature and timestamp could be stored privately until the author wishes to claim ownership at a later date. This might be compared to a privately-held NFT.

1. Introduction

Will anyone ever prove the identity of [Satoshi Nakamoto](https

	<Project>

	<!--
	Look in an external deployment folder (intended for build secrets) with the same name as the solution folder
	for any appsettings.json files where the environment name matches the publish profile. Include them as links
	under each .pubxml file so that they can be easily edited and accessed outside of the current repository.
	-->
	<ItemGroup>
	<None Include="..\..\Deployment\$([System.IO.Path]::GetFileName($(SolutionDir.TrimEnd('\\'))))\appsettings.*.json">
	<Link>Properties\PublishProfiles\%(Filename)%(Extension)</Link>

	/*
	* Based on: https://gist.github.com/jonathanduke/b3385b350b7fa02019ba9927c5fa3f5a
	* Public domain: http://unlicense.org/
	* Modify as you wish, but you are encouraged to leave this comment for future reference in case the original is updated.
	*/

	import 'dart:async';
	import 'dart:convert';
	import 'dart:typed_data';
	import 'dart:ui';

	import 'package:flutter/material.dart';

	typedef OffstageEvaluator<T> = bool Function(T value);

	class OffstageValueListenableBuilder<T> extends ValueListenableBuilder<T> {
	final Key? offstageKey;
	final OffstageEvaluator<T> offstageEvaluator;

	OffstageValueListenableBuilder({
	super.key,

	import 'package:flutter/material.dart';

	extension LocaleFallbackExtensions on Locale {
	/// Look up the most specific version of a localized string, falling back through the BCP 47 language-script-region hierarchy.
	String? getString(String? key, String? Function(String k) lookup) {
	final prefix = key != null ? '${key}_' : "";
	String? text;

	if (null != (text = lookup('$prefix${toString()}'))) {
	// full locale code (en_US, es_MX, fr_CA, zh_Hans_CN, zh_Hant_TW)

	# This is for converting a ripped movie to a 480p size so my kids can watch it on their tablets in the car.
	# I'm cropping off 276 pixels from the top and bottom, which means it's a 3840x2160 image with a 2.39:1 letterboxed video.
	# The width can vary based on the aspect ratio, but the height should always be 480px.
	# I'm hard-coding it to use H.264 and yuv420p and to downmix surround sound to regular stereo channels.
	# On some movies, I had to use -map 0:2 to get the 5.1 audio stream if the 7.1 was truehd and ffmpeg didn't like that.
	ffmpeg -i "4k.mkv" -vf "crop=iw:ih-552:0:276,scale=1146:480" -c:v libx264 -c:a copy -ac 2 -sn -pix_fmt yuv420p -map 0:0 -map 0:2 -crf 18 -map_chapters -1 "480p.mp4"

	# After getting the resolution right, follow this process to reduce the size of the video: https://trac.ffmpeg.org/wiki/Encode/H.264#twopass
	ffmpeg -y -i original.mp4 -c:v libx264 -b:v 1000k -pass 1 -an -f null NULL && ffmpeg -i original.mp4 -c:v libx264 -b:v 1000k -pass 2 -c:a aac -b:a 128k shrink.mp4

	// https://dartpad.dev/?id=dad879af094b27b24fd6070e1175e791

	// Pending feature request: https://github.com/dart-lang/sdk/issues/41717
	// Note: this requires Dart 2.14 and above (to support the >>> operator)

	class IntRange {
	// based on: https://stackoverflow.com/a/75928881
	static const int maxValue = (-1 >>> 1);
	static const int minValue = -1 - maxValue;
	}

	::::
	:: Original source: https://gist.github.com/jonathanduke/92eac20fe8a85eff8e8840b5d56551f9#file-git-list-worktrees-bat
	:: Public domain: http://unlicense.org/
	:: Modify as you wish, but you are encouraged to leave this comment for future reference in case the original is updated.
	::::
	@echo off
	setlocal EnableDelayedExpansion
	for /f "tokens=*" %%f in ('dir /a /s /b .git') do (
	if exist "%%f\*" (
	set "_dir=%%~dpf"

	// read a DD-WRT nvrambak_xyz.bin backup file and create "nvram set" commands FOR COMPARISON ONLY
	// NOTE: some values may have issues, so you can't just copy and paste the whole output or it can mess up your router
	// The format should be similar to processes to export from the router via the command line:
	// https://gist.github.com/Aikhjarto/5b1c6b5e5d373d8d60c004e075b29acc
	// https://gist.github.com/rambotech/d1e2486228c5e972c3c9c8936920f2fc
	var set = new List<string>();
	using var file = System.IO.File.OpenRead(args[0]);
	var buffer = new byte[0xFFFF];
	int len = 6;
	int count = file.Read(buffer, 0, len);