Abstract: A data processing system which protects the secrecy of confidential inforion includes a data processing machine with which an operator may carry on a confidential dialogue through a data transmitting device such as a keyboard and an auxiliary device in which is stored a predetermined permanent code key which controls access to the machine upon comparison to and recognition of a confidential code personal to the user. The auxiliary device may take the form of a card having an electronic integrated circuit means thereon and a plurality of contact members which are respectively connected to the circuit means by integrated connections. The contact members are designed to generate in response to external contact by a user operated stylus, a set of basic items of information corresponding to the confidential code personal to the user.

Abstract: A data processing system is provided which protects the secrecy of confidial data transmitted between a transmitting terminal and key, such as a credit card, which is used to authorize a dialogue between a data processing machine and an operator. A light pen is provided which is personal to each operator and which includes means for formulating the confidential data in a predetermined code and transmitting the coded information by means of an information carrying light wave. The light pen includes a keyboard which may be in the form of cursors movable along a longitudinal graduated scale which sets the coded data in accordance with the position of the cursors. To this end, the light pen houses an encoder, the output of which is fed to a shift register. The output of the shift register is modulated and fed to an optical-electrical transducer system which is screened to prevent unauthorized detection. The credit card receives the coded information through its own electrical transducer.

Abstract: A data processing system is provided which protects the secrecy of confidential data at the stages where it is formulated and transmitted to a card (first auxiliary member) having a code key thereon. The data processing system includes a data-processing machine having a device or terminal for transmitting data, including confidential data, and a plurality of first members auxiliary to the machine which are each intended to receive the confidential data from the transmitting device via the same transmission line and to process this confidential data. The transmitting device includes a plurality of second auxiliary members which correspond to respective ones of the first auxiliary members. Each pair of corresponding first and second auxiliary members include respective generators for generating first and second code keys and the system includes a means for causing one of the first code keys to correspond with one of the second code keys.