| 摘要 |
PROBLEM TO BE SOLVED: To execute a processing at high speed by constituting a digital signature generation processing based on an ellipse curve through the use of a method for effectively using an excess multiplication operation. SOLUTION: An excess operation after the generation of random numbers required for an ellipse curve ciphering processing and an excess operation in a signature generation processing are operated by using an excess multiplier 107. For effectively using the excess multiplier 107 even in an operation on an ellipse curve, a point on the ellipse curve is converted from a two-dimensional affine coordinate system into a three-dimensional coordinate system. Thus, an excess division operation in an addition operation on the ellipse curve is converted into an excess multiplication operation and the excess multiplier 107 can be used in the excess multiplication operation. In such a case, ABR<-1> modN, A<2> R<-1> modN and AR<-1> modN, which show a calculation object numeric value generated in an intermediate operation processing, are calculated by the multiplication operation of excess multiple length against positive integers A, B, N and R (A and B are input variables or intermediate variables, N is an input variable and R is a numeric value given as a constant). |
