Startup Nok Nok Labs has developed a security protocol that asks end users to substitute stronger authentication tools such as fingerprints and voice recognition for the usual user names and passwords.

Named after the classic knock-knock joke, Nok Nok Labs wants to revolutionize online identity authentication with tools that already exist on user devices, such as a camera, a touch screen and a microphone, said Phillip Dunkelberger, Nok Nok's CEO and founder of encryption company PGP Corp., which Symantec (s symc) Corp.