Masked nonlinear feedback shift register

摘要

An NLFSR of length k, configured to output a sequence of masked values x′i=xi+mi according to a masked recurrence x′n+k=f(x′n, . . . , x′n+k−1), the NLFSR including a nonlinear feedback function configured to compute f(x′n, . . . , x′n+k−1) so as to obtain a feedback value, a correction function configured to compute (mn, . . . , nn+k−1)+mn+k+h(mn, mn+k−1, xn, . . . , xn+k−1) to obtain a correction value c, and a corrector configured to correct the feedback value {circumflex over (x)}′n+k using the correction value c to obtain a corrected feedback value which forms x′n+k.

主权项

1. A nonlinear feedback shift registers (NLFSR) of length k, configured to output a sequence of masked values x′i=xi+mi, according to a masked recurrence x′n+k =f(x′n, . . . , x′n+k−1), the NLFSR comprising:
a nonlinear feedback function comprising a feedback circuit of gates and configured to compute f(x′n, . . . , x′n+k−) so as to obtain a feedback value; a correction function comprising a correction circuit of gates and configured to compute f (mn, . . . , mn+k−1)+mn−k+h(mn, . . . , mn+k−1,xn, . . . , xn+k−1)to obtain a correction value c; and a corrector connected to the correction function and configured to correct the feedback value using the correction value c to obtain a corrected feedback value which forms x′n+k, wherein miis a mask which is applied to xi,wherein the NLFSR comprises a shift register of a sequence of n registers configured to store the masked values x′n+k−1, . . . , x′n.