NONLINEAR ARITHMETIC UNIT, ENCRYPTION PROCESSOR, NONLINEAR ARITHMETIC METHOD, AND NONLINEAR ARITHMETIC PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide an encryption processing method wherein processing is performed at high speed by reducing the number of times of multiplication while securing the safety against power analysis.;SOLUTION: In a nonlinear arithmetic unit, a data input section 140 receives partial input P, and a random number input section 141 receives input of a modified random number M. A random number generating section 128 generates an arbitrary random number M' and a random number N having no correlation with the modified random number M. An exponentiation operation section 127 receives input of the partial input P, the modified random number M, the random numbers M' and N, calculates output data F_e (F_e=x^e+m') by using a polynomial wherein the exponentiation P^e of the partial input P, the random number M', the modified random number M, the partial input P, and a formula to be expressed only by Mx obtained by multiplying the modified random number M by data x contained in the partial input P and to be encrypted are added, and outputs it. At this time in the calculation, a formula expressed only by the modified random number M, random number added data P, and multiplication data Mx, and so transformed as to reduce the frequency of multiplication is used.;COPYRIGHT: (C)2006,JPO&NCIPI