A cryptographic processing method executed by at least one processor, the method comprising a multiplication of a point P of an elliptic curve on a Galois field by a scalar k, wherein the multiplication comprises the steps of: • storing a zero point of the Galois field in a first register, • executing a loop comprising at least one iteration, wherein one iteration of the loop comprises steps of: ∘ selecting a window of w bits in a non-signed binary representation of the scalar k, wherein w is a predetermined integer independent of the scalar k and is strictly greater than 1, ∘ calculating, by means of a doubling function, and storing, in at most w second registers, multiple points of P, wherein each multiple point is associated with a bit of the window and is of form ±2 i P where i is an integer, ∘ adding or not, in the first register, multiple points stored in the second register by means of an addition function, wherein each multiple point is added or not in the first register depending of the value of the bit of the window with which the multiple point is associated, wherein the loop ends once each bit of the non-signed binary representation of the scalar k has been selected in an iteration, • after the end of the loop, returning a value stored in the first register, the method being characterized in that: • if all the bits of the window selected during an iteration of the loop are zero, the iteration comprises at least one dummy execution of the addition function, and/or • if all the bits of the window selected during an iteration of the loop are non-zero, the multiple points to be added in the first register during the step are determined from a non-adjacent form associated with the window. • storing a zero point of the Galois field in a first register, • executing a loop comprising at least one iteration, wherein one iteration of the loop comprises steps of: ∘ selecting a window of w bits in a non-signed binary representation of the scalar k, wherein w is a predetermined integer independent of the scalar k and is strictly greater than 1, ∘ calculating, by means of a doubling function, and storing, in at most w second registers, multiple points of P, wherein each multiple point is associated with a bit of the window and is of form ±2 i P where i is an integer, ∘ adding or not, in the first register, multiple points stored in the second register by means of an addition function, wherein each multiple point is added or not in the first register depending of the value of the bit of the window with which the multiple point is associated, wherein the loop ends once each bit of the non-signed binary representation of the scalar k has been selected in an iteration, ∘ selecting a window of w bits in a non-signed binary representation of the scalar k, wherein w is a predetermined integer independent of the scalar k and is strictly greater than 1, ∘ calculating, by means of a doubling function, and storing, in at most w second registers, multiple points of P, wherein each multiple point is associated with a bit of the window and is of form ±2 i P where i is an integer, ∘ adding or not, in the first register, multiple points stored in the second register by means of an addition function, wherein each multiple point is added or not in the first register depending of the value of the bit of the window with which the multiple point is associated, • after the end of the loop, returning a value stored in the first register, • if all the bits of the window selected during an iteration of the loop are zero, the iteration comprises at least one dummy execution of the addition function, and/or • if all the bits of the window selected during an iteration of the loop are non-zero, the multiple points to be added in the first register during the step are determined from a non-adjacent form associated with the window.