The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 04, 1989
Filed:
Jul. 07, 1986
Hartmut Schrenk, Haar, DE;
Siemens Aktiengesellschaft, Berlin and Munich, DE;
Abstract
A method for controlling memory access to a user area and an initial code area of a main memory of a chip card includes carrying out an internal release procedure with a data comparison of an initial code from the initial code area and a data word from a terminal; firmly coupling addresses of the main memory and of a control memory to each other; marking several storage locations of the main memory as the initial code area with one control bit at a time in the control memory; marking a first code deposited in the associated storage location of the first code area as activated or deactivated with one further control bit at a time in the control memory; generating an initial release signal in a release procedure only if a storage location is addressed by an activated initial code and if agreement with the data word entered by the terminal prevails; and preventing generation of the initial release signal if a deactivated code word is addressed and/or if the respective first code does not agree with the data word, and an apparatus for carrying out the method.