GPG 
GNU Privacy Guard or GPG is an encryption system which has taken over from  PGP [ Pretty Good Privacy ] it was a great system, which kept data secret from every intruder with the possible exception of major government espionage operations like the NSA. The NSA has now been exposed as a bad tempered bunch of criminals but that is another theme.

PGP failed as encryption for the masses because people would not learn to use it. Given that so many of them use Facebook, Twitter et cetera you have to think a lot just do not care.

PGP started as open source then became closed source. Secret coding means that back doors could be built in. But now we have GNU Privacy Guard. It is open source so if you are a real programmer you can check the source code for yourself. Get it from http://www.gnupg.org/ It is the way forward. Use it or lose it.

 

PGP
PGP is short for Pretty Good Privacy and the name tells you what you need to know. PGP keeps your email private from any one prying. The American Government was so pleased by this approach to keeping speech free and private that they tried to put the author, Phil Zimmermann in prison.

The effectiveness is all that you need unless a major nation's government is after you. Version 6.5.8 is the last which came with publicly available source code. This means that it can be checked by anyone who can read C or C++. Later versions are not always trusted by the sincerely paranoid. The price/performance ratio is satisfactory. Phil gave it to us for free. Later versions can cost you money.

It turns out that Robert Hanssen, an American traitor used PGP to send messages to the KGB but they could not cope with this level of sophistication back in 1985. He is doing life.