Abstract: Operating procedure and device for the electronically authorized determination of an individual matter and for obtaining, in a reliably differentiating manner which is secure against forgery, the remotely authorized, individual authentication of a transaction requiring an authentication from an authorized person. The entire system is composed of two hardware components, an AIDA box which can be a pocket calculator equipped with special function keys, and an AIDA module which is a dual processor system with insertable AIDA cards containing special chips. By putting a personal identification number into the AIDA box and through the intermediary physical action on the chip, an identification number is calculated with the aid of an algorithm and displayed. An electronic signature is calculated and displayed by putting in the information to be authenticated. After transmission over a communications system, the calculated values are checked in the AIDA module.