fengli320

OpenSSL Cheat Sheet 🔐

Install

Install the OpenSSL on Debian based systems

sudo apt-get install openssl

Mounting VirtualBox shared folders on Ubuntu Server 18.04 LTS (Bionic Beaver)

This guide will walk you through the steps on how to setup a VirtualBox shared folder inside your Ubuntu Server guest.

Prerequisites

This guide assumes that you are using the following setup:

Oracle VM VirtualBox version 6.0.10 with Extension Pack installed
Microsoft Windows 7 SP1 as the host OS
A fresh install of Ubuntu Server 18.04.2 LTS as the guest OS

You could still make this guide work with other setups (possibly with some modifications to the commands and whatnot).

.gitkeep

A .gitkeep file tells github to do the opposite of its default behaviour, which is to ignore empty folders.

If you want to track an empty folder, or a folder with untracked files, create a 0kb file with the .gitkeep file extension in that folder.

touch FOLDER_NAME/.gitkeep

Create Root CA (Done once)

Last update: Nov 2025.

Create Root Key

Attention: this is the key used to sign the certificate requests, anyone holding this can sign certificates on your behalf. So keep it in a safe place!

openssl ecparam -genkey -name secp384r1 | openssl ec -aes256 -out rootCA.key

	"""
	This gist shows how to run asyncio loop in a separate thread.
	It could be useful if you want to mix sync and async code together.
	Python 3.7+
	"""
	import asyncio
	from datetime import datetime
	from threading import Thread
	from typing import Tuple, List, Iterable