Centre National De La Recherche Scientifique

Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Sorbonne Université

Karine Heydemann

Damien Courousse

Thierno Barry

Thomas Chamelot

A method for executing a machine code with a computer, including constructing a signature for a current instruction on the basis of signals generated by a stage of a hardware processing path, this stage being a decoder or a stage following the decoder in the hardware processing path, and on the basis of the preceding signature constructed for an instruction which precedes it, then checking the integrity of the executed machine code by comparing the signature constructed for the current instruction with a prestored reference signature, then only when the integrity of the current instruction has been checked successfully, decrypting a cryptogram of the following instruction using the signature constructed for the current instruction.

Method for fetching encrypted instructions, decoding and executing decrypted instructions, and comparing instruction signatures to ensure execution integrity

An execution method includes supplying of a machine code, the machine code being formed by a succession of base blocks and each base block being associated with a signature and comprising instructions to be protected. Each instruction to be protected is immediately preceded or followed by an instruction for constructing the value of the signature associated with the base block. Each construction instruction is coded on strictly less than N bits, and each word of the machine code which comprises at least one portion of one of said instructions to be protected also comprises one of the construction instructions so that A is not possible to load an instruction to be protected into an execution file, without at the same time loading a construction instruction which modifies the value of the signature associated with the base block when it is executed.

Method for executing a machine code formed from blocks having instructions to be protected, each instruction associated with a construction instruction to modify a signature of the block

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Paris, France

Karine Heydemann