Patent ID: 8817973
Filing Date: 2014-08-26
Classification: G06F,H04L

Abstract:
1. An encrypting method performed by an encrypting apparatus having a processor, the encrypting method having a countermeasure function against power analyzing attacks by performing an exponential remainder calculation y=a d (mod n) from an exponent d expressed by u-bit binary, input data a, and a modulo n to encrypt the input data a, the encrypting method comprising: calculating, using the processor, a′=a calculating, using the processor, y=(a) calculating, using the processor, y=y×a (mod n) with d outputting the calculated y as encrypted data y=a wherein when g is a least significant bit of d and f is higher order u−1 bits of d, by using f and g satisfying d=2×f+g, a calculation of a