The method and system of the invention utilizes a private key of a public-key cryptosystem key pair to encrypt a non-secret password into a digital signature. The password and the digital signature are then encoded and stored on a magnetic stripe or other memory device of the card. To effect a transaction,...http://www.google.de/patents/US4879747?utm_source=gb-gplus-sharePatent US4879747 - Method and system for personal identification
