< 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.
http://world.std.com/~reinhold/diceware.page.html .
(1996-12-21)