Actually this idea of writing a post about programs for sending encrypted emails popped up today morning.
Why was this ?
Because there are many (legal and illegal) thieves on internet who spy on you to get to know what you were doing and sometimes what are you about to do. The most popular example of such spying (or espionage) is NSA. They get access to your emails without your password, because they have the power to spy on anyone ( this is what I meant by saying LEGAL thieves ).
To make this process difficult many journalists and whistle-blowers use GPG (which is actually an alternative for Pretty Good Privacy) so that they need the private key to unlock the encrypted message.
The process of sending encrypted email is not a big task, it could actually be as easy as sending a normal email, but with some more commands (if you are using a Unix or Ubuntu machine).
"GnuPG uses public-key cryptography so that users may communicate securely. In a public-key system, each user has a pair of keys consisting of a private key and a public key. A user's private key is kept secret; it need never be revealed. The public key may be given to anyone with whom the user wants to communicate." From The GNU Privacy Handbook
GnuPG, GPG, PGP and OpenPGP
The terms "OpenPGP", "PGP", and "GnuPG / GPG" are often used interchangeably. This is a common mistake, since they are distinctly different.
- OpenPGP is technically a proposed standard, although it is widely used. OpenPGP is not a program, and shouldn't be referred to as such.
- PGP and GnuPG are computer programs that implement the OpenPGP standard.
- PGP is an acronym for Pretty Good Privacy, a computer program which provides cryptographic privacy and authentication. For more information, see this Wikipedia article.
- GnuPG is an acronym for Gnu Privacy Guard, another computer program which provides cryptographic privacy and authentication. For further information on GnuPG, see this Wikipedia article.
Generating an OpenPGP Key
The core package required to start using OpenPGP, gnupg, is installed by default on Ubuntu systems, as is seahorse, a GNOME application for managing keys. It is called "Passwords and Keys" in Ubuntu.
There are several programs which provide a graphical interface to the GnuPG system.
Enigmail, an OpenPGP plugin for Mozilla Thunderbird.
Enigmail was available in the "Main" repository through Intrepid, but can be found in the "Universe" repository since Jaunty.
sudo apt-get install enigmail
GNU Privacy Assistant is a graphical user interface for the GnuPG (GNU Privacy Guard).
GPA is available in the "Universe" repository.
sudo apt-get install gpa
Seahorse is a GNOME application for managing encryption keys. It also integrates with nautilus, gedit, and in other places for encryption operations.
Seahorse is available in the "Main" repository.
sudo apt-get install seahorse
KGPG is a simple, free, open source KDE frontend for gpg.
KGPG is available in the "Main" repository since Intrepid, or the "Universe" repository in earlier releases.
sudo apt-get install kgpg
Kleopatra is another KDE frontend for gpg that is integrated with the KDE PIM (although you need to install it separately for now).
Kleopatra is available in the "Universe" repository and it includes S/MIME backend:
sudo apt-get install kleopatra
How to use these tools will be published in the upcoming days.