A proposed password-less and hands free payment setup for Paypal.
The user enters the store. The app on the phone automatically connects to open wifi with a particular matching SSID. The users' name get appended to the list of available Paypal users in the screen and the counter computer can initiate a payment request by simply entering the amount. The Paypal user receives a payment request on the phone and the amount is read out loud. The user can simply shake the phone to authorize the payment and do nothing to cancel the payment.
Android client for the setup @ Shake-Client