Trusted Logic

Renaud Marlet

Alexandre Frey

Daniel Le Metayer

Xavier Leroy

Arnaud Venet

Eric M Vetillard

Patrice Hameau

Nicolas Regnault

Dominique Bolignano

The inventive method for controlling access to data which is used by reference in a program execution system (including processes and aims) during the program execution consists in memorising by the system the totality of references obtainable by said program with the aid of means considered legal, before any operation which can be prohibited if it relates to values which are not legal references, in verifying by the system whether said values are amongst the legal references memorized for the program and in accepting or rejecting the operation, respectively.

Control of data access by dynamically verifying legal references

The inventive method for controlling a program execution integrity by verifying execution trace prints consists in updating the representative print of an execution path and/or data applied for a program execution, comparing the actual print value (dynamically calculated to an expected value (statistically fixed, equal to a value of the print if the program execution is not disturbed) at a determined program spots and in carrying out a particular processing by the program when the actual print differs from the expected value.

Method for controlling program execution integrity by verifying execution trace prints

The inventive method for determining operational characteristics of a program includes a verification procedure involving the following stages: the first stage for expressing the operational characteristics of the program in the form of functions related to events producible during possible executions of the program, a second stage for simultaneously estimating, by program analysis, the program structure, the possible ways of execution and values used at different program points and the third stage for determining said characteristics by calculating associated functions by means of information extracted with the aid of the analysis.

Method for determining operational characteristics of a program

A method for compressing an interpreted object code in a system using an interpreter, by identifying, in the interpreted object-coded program, similar non-contiguous groups of instructions, of arbitrarily complex structure, by replacing all or part of said groups in the interpreted object code of the program with newly-created specialized instructions and by instrumenting the interpreter and/or the interpreted object code of the program so as to render it capable of implementing the newly-created instructions.

Method for compression of object code interpreted by tree-structured expression factorization

The invention concerns a method for compressing program code for execution in a system with few physical resources. This method comprises a semantic analysis of the code as to identify the objects accessed at each program point and to replace in this program groups of instructions used to access the objects by more compact specialised instructions.

Semantic analysis based compression of interpreted code by replacing object instruction groups with special instruction specifying a register representing the object

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Paris, France

Renaud Marlet