Patent ID: 8934631
Filing Date: 2015-01-13
Classification: G06F,G09C,H04L

Abstract:
1. A decompressing apparatus comprising: an input microprocessor that inputs trace expression data, in which an element in a subgroup of a multiplicative group of a finite field is trace-expressed, and additional data, the additional data being obtained based on the trace expression data and affine expression data in which the trace expression data is affine-expressed; a calculating microprocessor that calculates a plurality of solutions of simultaneous equations derived by the trace expression data; a first selecting microprocessor that selects any of a plurality of items of affine expression data in which the element is affine-expressed based on the additional data, the affine expression data being found from the solutions; and a decompressing microprocessor that decompresses the selected affine expression data to the element, wherein the calculating microprocessor comprises: