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

Gaëtan Leplus

Olivier Savry

A method for executing a machine code using a microprocessor includes, after an operation of decoding a current loaded instruction, constructing a mask from the signals generated by an instruction decoder in response to decoding of the current loaded instruction by the decoder. The constructed mask varies as a function of the current loaded instruction. Subsequently, before an operation of decoding a next loaded instruction, the next loaded instruction is unmasked using the constructed mask.

Generating masks from decoded instructions to apply to fetched instructions for unmasking

A method for executing a function, secured by temporal desynchronization, includes when a first legitimate instruction is loaded, noting the opcode of this first legitimate instruction, then constructing a dummy instruction on the basis of this noted opcode, the dummy instruction thus constructed being identical to the first legitimate instruction except that its operands are different, then incorporating the dummy instruction thus constructed into a sequence of dummy instructions used to delay the time at which a second legitimate instruction is executed.

Method for executing a function, secured by temporal desynchronization

A method of executing machine code using a microprocessor includes, for each datum D, computing a code Cusing a relationship C=Q(D)=P o F(D), where P is a predetermined function, Fis a function defined by the following relationship: F(D)=To . . . o To . . . o To T(D), and Tis αconditional transposition, configured by a secret parameter αr, that permutes two blocks Band Bof bits of the datum Don the basis of the value of the parameter αr. The method also includes computing a code Cusing the following relationship: C=C& C& . . . & C, where Cto Care the codes associated with data Dto Dcombined with one another by a Boolean operation D& D& . . . & Dwhere the '&' symbol designates the Boolean operation.

Growing community of inventors

Grenoble, France

Gaëtan Leplus