公开(公告)号：EP1732052A4

公开(公告)日：2009-07-08

申请号：EP05727024

申请日：2005-03-22

Applicant: PANASONIC CORP

Inventor： FUTA YUICHI ,  OHMORI MOTOJI ,  SHIZUYA HIROYUKI ,  MAMBO MASAHIRO ,  YAMAMICHI MASATO

IPC: G06F7/72 ,  G06F7/50 ,  G09C1/00

CPC classification number: G06F7/72 ,  G06F7/723

Abstract: There is provided a computer system which makes it difficult to analyze a calculation content. A power calculation unit (262) performs the following calculation for the input data "a" and "b": ga = g mod n, gb = g mod n. Next, a multiplication unit (264) performs the following calculation for ga and gb: gab = ga x gb mod n. Next, a discrete logarithm calculation unit (266) calculates ci mod pi - 1 which satisfies gab = g mod pi (i = 1, 2, ..., k). Next, a CRT unit (267) calculates "c" which satisfies ci = c mod pi - 1 (i = 1, 2, ..., k) by the Chinese remainder theorem (CRT).