Here you can download a copy of the PGP Intro to Crypto documentation that originally came with Pretty Good Privacy by Phil Zimmermann. I first learnt of PGP at a lecture given by Phil Zimmermann organised by Ross Anderson
PGP has been superseded by OpenPGP and GPG.
But details of the original PGP can be found via Phil Zimmermann's webpages. including reasons to use PGP
Shell user friendly PGP how-to
I have several OpenPGP keys including an old RSA one which I used back in 1995 but it uses the patented IDEA algorithm later ones don't. My latest one was created with GPG with is compatible with OpenPGP, which is used by later versions of PGP and it's successors from Boardcom (which purchased Symantec). Please use my latest key. I have also lost private keys I made at some points.
I have used Kmail which integrates with GPG, and used KGpg for key management. If you use MS Windows or MacOS I advise you to try Thunderbird email client which has OpenPGP encryption now intergrated into Thunderbird itself. I also used OpenKeyChain with K9Mail on Android. If you just use webmail then there are various browser plugins that help, but these have tended to come and go in past, so best to look out for latest up to date regularly bug fixed one available.
For a more private phone check out Graphene OS.
If you want hide IP addresses used by you while web surfing use TOR ( https://tor.eff.org/ ) or try finding & using a Virtual Private Network service such as OVPN, PrivateInterNetAccess, Perfect Privacy, NordVPN, Njalla VPN (merged with IPredator), or you can use the free over WARP 1.1.1.2 alternative DNS service from Cloudflare. Also check out up and coming NYM.
If you want to use encryption to the email address you already use on home computer get a copy of PGP or GPG and you can send encrypted mail to other PGP users like me using my public GPG key, once one has read the user guide and set it up it is quite straight forward to use.
More useful info can be found from the Rise Up security pages.
FLOSS Manuals: Introduction to Mail Encryption PGP
Also see: computing page and internet page.