operating system A string of words and characters that you
type in to authenticate yourself. Passphrases differ from
passwords only in length. Passwords are usually short - six
to ten characters. Passphrases are usually much longer - up
to 100 characters or more. Their greater length makes
passphrases more secure. Modern passphrases were invented by
Sigmund N. Porter in 1982.
Phil Zimmermann's popular encryption program
PGP, for
example, requires you to make up a passphrase that you then
must enter whenever you sign or decrypt messages.
(1996-12-21)