In an authenticated key-agreement protocol that uses public key cryptography, perfect forward secrecy (or PFS) is the property that ensures that a session key derived from a set of long-term public and private keys will not be compromised if one of the (long-term) private keys is compromised in the future. Forward secrecy has been used as a synonym for perfect forward secrecy [1], since the term perfect has been controversial in this context. However, at least one reference [2] distinguishes perfect forward secrecy from forward secrecy with the additional property that an agreed key will not be compromised even if agreed keys derived from the same long-term keying material in a subsequent run are compromised.

Occultum, meaning concealment or secrecy.

Sworn to secrecy means that you are trusted not to tell a secret.

Angerona was considered to be the Goddess of Secrecy and Protector of Rome.

Secrecy - book - has 432 pages.