Researchers suggest haptics and audio for discreet password input

from Engadget: 

>>Researchers Andrea Bianchi, Ian Oakley and Dong-Soo Kwon have some ideas for overcoming that little problem though, and recently put together a video demonstrating a few of the possibilities they've come up with. All of those rely on haptic input systems -- either on their own or in conjunction with some audio output (through headphones for privacy).