Pretty Good Privacy (PGP)

Pretty Good Privacy (PGP) is a methodology used for encrypting and decrypting digital files and communications over the Internet. It was released with the BassOmatic symmetric key algorithm but later replaced by the International Data Encryption Algorithm (IDEA) to circumvent certain BassOmatic flaws.

Created by Phil Zimmerman in 1991, PGP was initially designed for email security. PGP works on the public key cryptography mechanism, where users encrypt and decrypt data using their respective public and private keys. PGP uses a symmetric encryption key to encrypt messages, and a public key is used with each sent and received message. First, the receiver must use its private key to decrypt the key and then decrypt the message through the decrypted symmetric key.

PGP also provides data/file integrity services by digitally signing messages, allowing receivers to learn whether or not message confidentiality is compromised.

PGP is also used to encrypt files stored on a computer and/or complete hard disk drives.