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Use Certbot Standalone Mode to Retrieve Let’s Encrypt SSL Certificates

Watch out! This tutorial is over 7 years old. Please keep this in mind as some code snippets provided may no longer work or need modification to work on current systems.

Let’s Encrypt is a service offering free SSL certificates through an automated API. The most popular Let’s Encrypt client is EFF‘s Certbot.

Certbot offers a variety of ways to validate your domain, fetch certificates, and automatically configure Apache and Nginx. In this tutorial, we’ll discuss Certbot’s standalone mode and how to use it to secure other types of services, such as a mail server or a message broker like RabbitMQ.

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Create a virtual encrypted disk within a file and mount it as a real disk

Watch out! This tutorial is over 7 years old. Please keep this in mind as some code snippets provided may no longer work or need modification to work on current systems.

VeraCrypt is a free open source disk encryption software for Windows, Mac OSX and Linux based on (the now defunct) TrueCrypt 7.1a. Features include:

  • Creates a virtual encrypted disk within a file and mounts it as a real disk.
  • Encrypts an entire partition or storage device such as USB flash drive or hard drive.
  • Encrypts a partition or drive where Windows is installed (pre-boot authentication).
  • Encryption is automatic, real-time(on-the-fly) and transparent.
  • Parallelization and pipelining allow data to be read and written as fast as if the drive was not encrypted.
  • Encryption can be hardware-accelerated on modern processors.
  • Provides plausible deniability, in case an adversary forces you to reveal the password: Hidden volume (steganography) and hidden operating system.

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GIMP as a Photoshop Alternative

Watch out! This tutorial is over 7 years old. Please keep this in mind as some code snippets provided may no longer work or need modification to work on current systems.

For those of you who are unaware of GIMP, here is how the software describes itself:

GIMP is the GNU Image Manipulation Program. It is a freely distributed piece of software for such tasks as photo retouching, image composition and image authoring. It works on many operating systems, in many languages.

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How To Create a SSL Certificate for Apache

Watch out! This tutorial is over 7 years old. Please keep this in mind as some code snippets provided may no longer work or need modification to work on current systems.

SSL is based on the mathematical intractability of resolving a large integer into its also-large prime factors. Using this, we can encrypt information using what’s called a “private-public key pair”. Certificate authorities can issue SSL certificates that verify the authenticity of such a secured connection, and on the same note, a self-signed certificate can be produced without third-party support. By the end of the tutorial, you will have a web server accessible via HTTPS using a self-signed certificate.

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The PDF Toolkit

Watch out! This tutorial is over 8 years old. Please keep this in mind as some code snippets provided may no longer work or need modification to work on current systems.

Creating and reading PDF files in Linux is easy, but manipulating existing PDF files is a little trickier. Countless applications enable you to fiddle with PDFs, but it’s hard to find a single application that does everything. The PDF Toolkit (pdftk) claims to be that all-in-one solution. It’s the closest thing to Adobe Acrobat that we’ve found for Linux.

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How To Set Up SSH Keys

Watch out! This tutorial is over 8 years old. Please keep this in mind as some code snippets provided may no longer work or need modification to work on current systems.

SSH keys provide a more secure way of logging into a virtual private server with SSH than using a password alone. While a password can eventually be cracked with a brute force attack, SSH keys are nearly impossible to decipher by brute force alone. Generating a key pair provides you with two long string of characters: a public and a private key. You can place the public key on any server, and then unlock it by connecting to it with a client that already has the private key. When the two match up, the system unlocks without the need for a password. You can increase security even more by protecting the private key with a passphrase.

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