The invention discloses a white-box
password nonlinear coding protection method based on combination of table look-up and disturbance scrambling. The white-box
password nonlinear coding protection method comprises the following steps of: averagely dividing 32-bit sensitive variables in a
password algorithm operation process into four sets, namely x<0,0>, x<0,1>, x<0,2> and x<0,3>, and sequentially performing nonlinear scrambling shown in the specification; adding disturbance information (beta*, Y, phi*), and calculating beta*=F(x<0,0>, x<0,1>, x<0,2> and x<0,3>) as an initial disturbance item; sequentially transforming results in two steps through T<3>, T<2>, T<1>, T<0> and phi*; taking an output result as column promiscuous transformation; and then, sequentially performing nonlinear displacement through Q<3>, Q<2>, Q<1>, Y and Q<0> to obtain an input variable for the next round of iteration, such that a final output result of a
white box is obtained. According to the invention, nonlinear bijection transformation of internal and external coding is adopted simultaneously; because the algebraic time of a single
S box is not beyond 8 and the algebraic time cannot be increased by a column promiscuous part and external
radiation scrambling coding, required operation is relatively low; furthermore, when an external algebra interpolation
attack occurs, a main key cannot be recovered directly; an equivalent decoding Boolean
system is constructed; and thus, the safety of the white-box password nonlinear coding protection method disclosed by the invention is relatively high.