====== GnuPG introduction tutorial ======
===== Introduction =====
This document describes how to use gnupg (gpg) tool to make a basic (everyday) operations, described in [[documentation:gpg-keys|this page]]. Also, it's highly recommended to read mentioned document first.

[[https://gnupg.org/|GnuPG]] is a standard tool to use. It's a text-based console application, but it's a way more ease to use comparing with a graphical application. 

===== Getting GnuPG =====
==== Mac OS X ====

=== Install brew tool ===
Brew tool is a tool of [[wp>Homebrew_(package_management_software)]], so, in order to install it, please do the following:
  * Open a terminal found on /Applications/Utilities/
  * Run ''xcode-select --install''
{{documentation:install-command-line-tools-os-x.jpg}}
  * Click install button on the dialog
{{documentation:confirm-install-command-line-tools-mac-os-x.jpg}}
  * Wait until complete
{{documentation:downloading-command-line-tools.jpg}}

The full article might be found at http://osxdaily.com/2014/02/12/install-command-line-tools-mac-os-x/
  * Run in terminal the following ''/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"''

=== Brew ===

It's an easy to do in MacOS using brew. Just run in the terminal (mentioned early): ''brew install gpg''

==== Debian-based OSes (ubuntu, debian, devuan) ====
You need a sudo access in order to install a package. 

Open your favourite terminal and type ''sudo apt-get install gpg''.

Please note, in most cases gpg is already installed. 

==== SuSe/OpenSuse ====
The same requirements.

Open your favourite terminal and type ''sudo zypper install gpg''.

Please note, in most cases gpg is already installed. 

==== Other linuxes/BSDs ====
Use your own package manager, or compile GnuPG from source. 

==== Windows ====
Under windows it's possible to get it running via cygwin.

===== Using GnuPG =====

==== Key creation ====
In order to create a key pair type in terminal the following: ''gpg --full-generate-key''
{{documentation:gpg-create-1.png}}

Choose first method e.g. RSA and RSA.

{{documentation:gpg-create-2.png}}

Choose 4096 bits key long (it's more technically secure).

{{documentation:gpg-create-3.png}}

We'd recommend to choose 2 year lifespan.

{{documentation:gpg-create-4.png}}

Finally type your name, email and comment for the key pair (this is optional, you can leave it blank). You will be asked to type a passphrase to encrypt your private key with.

**NOTE:** Don't forget your passphrase, you can loss your private key without passphrase.
 
After this please be patient, some time is required to generate a key pair.

==== Import public key ====

To import someone's else public key all you need is type in terminal ''gpg --import <filename of the public key>''

==== Commit your own public key ====

To publish your public key you need to provide it first. To get a file with your own public key, just type the following in terminal: ''gpg --export --armor 'yourname@example.com' > yourname.asc''

==== Sign the data ====

==== Data encryption ====

=== Encrypt ===
To encrypt some data (e.g. file in the example below) you need to know a recipient and his/her public key. On the example below we're encrypting data in file secret.pdf for alice@askele.com: ''gpg -r 'alice@askele.com' -e secret.pdf''

Result file will be secret.pdf.gpg

=== Decrypt ===
In order to decrypt some data (e.g. file) you need to type the following (assuming you receive secret.pdf.gpg): ''gpg -d secret.pdf.gpg > secret.pdf''

Result will be stored in secret.pdf which is a plain (decrypted) data.