Many computer programs come with password or encryption options.
Usually these programs use only a very simple code which can be quickly broken down by Factoring , a mathematical technique. PGP uses a more complex code. Because only the most advanced government intelligence agencies have the ability to decrypt PGP codes, it offers enough privacy for most missions workers. Your public key is used to code a message for you. You can make your public key available to anyone, even your enemies, because only your private key can unlock messages coded with it.