Using PGP encrypted emails nobody except the sender and the intended recipient will be able to read and understand the contents. Below is a quick guide to encryption.
Each user needs three things, basically: PGP encryption software, a key pair and public keys of contacts. It isn't hard and here’s how to do it.
Step 1: Install PGP software
There are options. I recommend using GnuPG or, for Linux, KGpg. Or, if you use webmail, go to your browser’s plugin site and search for a PGP implementation. Or go to download.com and search for PGP to find free software for PGP. Or buy Symantec PGP. Just like people can send each other email without worrying which email client the recipient use for reading it, neither does the software people use for PGP matter much.
Step 2: Create a key pair
You will use your private key to encrypt things (files, emails). Others will use your public key to encrypt things for you. Follow instructions in the software for creating a key pair (usually a guide will launch after install). Do not forget your passphrase (aka password) and keep it well secured. You might also want to keep a backup of the key files or install them on more than one devices/computers.
Step 3: Exchange public keys
Send your public key to the contacts that need it. Or put it on your website or on a public key server. If you’re paranoid, copy it to a USB stick, put the stick in a brown envelope and hand it over only to people you meet in back alleys. Similarly, acquire the public keys you need from your contacts. You can download the public key for firstname.lastname@example.org right from the site. In your PGP software, find the option to import a key, then browse to the file location. Or simply try clicking the key file and see if the PGP software reacts.
Step 4: Enjoy the privacy
PGP is pretty good privacy. The mathematics says the NSA has an astronomical chance of hacking your key given enough time and a couple of their supercomputers. Other than that you should be safe.
Remember, however, that whoever you communicate with using PGP can still share your stuff. The security of your contacts is still a matter of trust. Also remember that prolific hackers and authorities alike will be able to see who you communicate with and how much. (That’s part of the reason Wikileaks required the use of Tor as well as PGP.) And remember that using PGP is no different than having a very heavy safe in your office - you’ll still be required to open it if a judge tells you to.
That being said, below is a complete list of all my passwords. That’s how i trust PGP ;-)
-----BEGIN PGP MESSAGE-----
Version: GnuPG v2.0.19 (GNU/Linux)
-----END PGP MESSAGE-----
Face the facts: We can’t trust secretive US agencies, the Russian mafia nor the Chinese military hackers to not snoop on our mostly mundane (yet, given our epicurean civilizational state of democracy which also entitles us to bomb lesser countries, perfectly justifiably private) chatter. But everyone can do their share to make confidentiality a norm.