What does PGP (Pretty Good Privacy) mean?
Introduced in 1991 and formalized with RFC 2440 and RFC 4880, PGP uses a combination of public-key and symmetrickey cryptography to ensure that messages can be delivered without a third party gaining access to the contents of the message. It also allows for a message to be signed so that the author of the message is indisputable. Many different algorithms can be used for the encryption, but the most commonly used methods are RSA for the public key crypto, and AES for the symmetric cipher. It is extremely important that the public key of any party be fully verified in order to know that the message is being delivered to the correct recipient or is from the correct sender.