Query-directed passwords
A classical tradeoff in the field of user authentication is between user convenience and system security. Should users authenticate themselves with their mother's maiden name, which is easily recalled but not very secure; or should they memorize a long, random password that is secure but unmemorable? In recent years, tokens and biometrics have been offered as the answer to this convenience-versus-security conflict; however, these require infrastructure modifications. We introduce query-directed passwords (QDP), an authentication procedure based on questions and answers  where the answers are known, not memorized. QDP is particularly convenient for infrequent use, such as monthly or yearly authentication to seldom-accessed accounts. Applications are described that capitalize on advantages of QDP. One of these is an automated password recovery system where testing showed a reduced use of Help Desk personnel for repeated, forgotten passwords from 20% to 2.7%. We discuss other applications, experimental results, and future research directions.
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