Patent ID: 9031234
Filing Date: 2015-05-12
Classification: H04L

Abstract:
1. An encryption device that performs encryption processing using a secret key and calculates a single encrypted data to be finally outputted as a result of the encryption processing from plain data, the encryption device comprising: one or more hardware processing comprising: a storage unit; an input unit that receives plain data; a first partial encryption unit that calculates first intermediate data from the plain data and stores the first intermediate data in the storage unit; a generation unit that generates a round key, which is used in calculations for the first intermediate data and N-th intermediate data (where N is an integer equal to or greater than 2), from the secret key; a second partial encryption unit that calculates (i+1)th intermediate data on the basis of i-th intermediate data (where i is an integer equal to or greater than 1 and smaller than N) and the round key, and stores the (i+1)th intermediate data in the storage unit; a third partial encryption unit that performs an arithmetic operation including predetermined conversion for mixing the N-th intermediate data, calculates (N+1)th intermediate data, and stores the (N+1)th intermediate data in the storage unit; a fourth partial encryption unit that obtains the single encrypted data to be finally outputted as the result of the encryption processing by performing an arithmetic operation including inverse conversion of conversions on the (N+1)th intermediate data; and an output unit that outputs the encrypted data.