PROTECTION OF A MODULAR EXPONENTIATION CALCULATION

摘要

A method of protecting a modular exponentiation calculation executed by an electronic circuit using a first register and a second register, successively comprising, for each bit of the exponent: a first step of multiplying the content of one of the registers, selected from among the first register and the second register according to the state of the bit of the exponent, by the content of the other one of the first and second registers, placing the result in said one of the registers; a second step of squaring the content of said other one of the registers by placing the result in this other register, wherein the content of said other one of the registers is stored in a third register before the first step and is restored in said other one of the registers before the second step.

主权项

1. A method, comprising:
protecting an electronic circuit against attack during an execution of a modular exponentiation calculation by an electronic circuit using a first register and a second register, by: successively, for each bit of an exponent of the calculation:
storing content of one of the first and second registers in a third register, the one of the first and second registers being based on a state of a current bit of the exponent;multiplying content of the other one of the first and second registers by the content of the one of the first and second registers, and storing a result of the multiplication in said other one of the first and second registers;storing content of the third register in the one of the first and second registers; andsquaring content of the one of the first and second registers and storing a result of the squaring in the one of the first and second registers.