|(operating system)||passphrase - 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.