A method for facilitating biometric security in a smartcard-reader transaction system is provided. The method includes determining if a transaction violates an established rule, such as a preset spending limit. The method also includes notifying a user to proffer a biometric sample in order to verify...http://www.google.com.hk/patents/US7594612?utm_source=gb-gplus-share專利 US7594612 - Smartcard transaction method and system using retinal scan recognition
