Siemens Aktiengesellschaft

Karl-Hermann Witte

Maximilian Walter

Jan Richter

Andreas Maximilian Schenk

Ulrich Taschke

A method, a device and computer program for recording a plurality of events in an encoded tracer variable in a security-oriented computer program, wherein each event is recorded as a value in the encoded tracer variable, where in order to simultaneously record multiple events from the values for the events, a total value is first calculated which is then recorded in the encoded tracer variable, such that multiple independent consistency criteria can be advantageously processed simultaneously to detect and propagate errors or other events and such that by virtue of the simultaneous processing, many dynamic effects are prevented during the detection and propagation of errors/events, thus allowing for the necessary reduced complexity of security programs.

Method for recording a number of events in an encoded tracer variable in a security-oriented computer program

A method, device and computer program product for securing access to an encoded variable in a computer program with a plurality of encoded variables that each having its own dynamic signature, wherein when the encoded variable is accessed, the dynamic signature of the variable is modified, where the sum value for all dynamic signatures of all other encoded variables is controlled in an encoded tracer variable, the sum value being controlled in the tracer variables is adapted if a dynamic signature of one of the encoded variables is modified, the encoded variable is compared with the sum value stored in the encoded tracer variable to monitor the sum of the dynamic signatures, and where an error handling process is initiated in the event of a discrepancy such that all signatures in an arithmetically encoded program can be managed in a high-performance manner regardless of the complexity of the program.

Method and device for securing access to encoded variables in a computer program

A method for protecting data in a data memory against an undetected change, wherein a functional variable x is encoded via a value, an input constant, an input signature and a timestamp D into a coded variable, where the functional variable is normalized relative to a base to form the integer value from the functional variable.

Data processing system and method for protecting data in a data memory against an undetected change

In a method in a computer system for recoding a coded intermediate variable into a recoded result variable a product is formed by multiplying an input constant by an input variable to be coded. The coded intermediate variable is formed as a function of the product and a multiplicative inverse is determined on the basis of the input constant. The multiplicative inverse is applied to the coded intermediate variable, so that no uncoded or partially uncoded interim result is produced and/or an error information potentially contained in the coded intermediate variable is still detectable in the interim result.

Method in a computer system, computer program and data processing system

A method for storing and propagating error information in computer programs, in which a globally valid error variable is used for storing and propagating the error information, wherein for each recognized error a nonzero value for the error is added to the error variable as error information with a respective stipulated arithmetic sign, and wherein the value is formed from a discrepancy in the content of a coded variable from an expected value. This combination and integration of a separate global propagation variable with values derived from an error, particularly by virtue of detected discrepancies in the known error recognition and propagation paths using operations and operands in 'coded processing', achieves an increased propagation certainty.

Method for storing and propagating error information in computer programs

A method for a safety-oriented industrial automation component, wherein the controller is connected to the automation component by a data link includes providing, by a user, an input to the controller at a first user interface. The controller transmits a result of the input to the automation component. The result of the input is used in the automation component to calculate a first test value. The input is converted into a status display in the controller and is output at a second user interface. Here, the user or another user acknowledges the status display by inputting a confirmation, after which a second test value is formed from the status display and the confirmation in the controller, and the second test value is transmitted to the automation component. Finally, the first and second test values are compared in the automation component and the result of the input is used if the comparison is positive.

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Nürnberg, Germany

Karl-Hermann Witte