The arbitrator uses these keys to send each participant a random session key that will be used for the communication. PGP PGP stands for Pretty Good Privacy. It is a freeware electronic-mail security program designed by Philip Zimmermann. The US government is upset at him for distributing the algorithm internationally as published source code. A Private key is known only to a single person.
Security depends on keeping that information secret.
With a private key, a person can sign a document which others can verify by using the person's public key. Alternatively, anyone can use someone's public key to encrypt a message that can only be read by the person who knows the associated private key. Public key Public key cryptography refers to a variety of patented techniques which use a pair of private and public keys for authentication and encryption. Diffie-Hellman, RSA, and SKIP are examples of security protocols based on public key cryptography. Although private and public keys can be used to authenticate participants in a secure communication, the algorithm is too cumbersome to use for the entire communication.