PGP is a kind of freeware, or software that is distributed to the public without any charge. It was first developed by Philip Zimmerman in 1991, but has undergone several improvements and changes. For example, companies that have acquired it tried to establish some kind of profit model by offering free features but reserving some additional services for paying members.
With the number of PGP versions it is important for people to look at the source code, and a digital signature that verifies that it is an authentic copy. The next question, of course, is which version to use. Some people say that it is best to use the original, even if it is not as convenient as the later versions. They say that some graphic user interfaces (or GUI) that were introduced by third parties have led to security issues. The original version is also smaller and will take up less computer memory. Unfortunately the original PGP requires manual, command line use.
Another version, the PGP version 6.5.8 freeware (NAI) included capabilities like Outlook, Outlook Express, Netscape and Eudora. Other parties provided compatible plug ins for Pegasus Mail or Bat! One valued feature was the plug in forVirtual Private Network (VPN).
PGP releases after version 6.5.8 did not use the original source code, causing Zimmerman to leave the company. The public, unhappy with the program, also stopped using PGP. Only when an unaffiliated programmer called Imad Faiad decided to re-incorporate the original code into further releases did the public begin using PGP again. Of his vrsions, build 08 is most popular, because it fixes some bugs and includes useful enhancements like being able to use large keys.