Patent ID: 8094811
Filing Date: 2012-01-10
Classification: H04L

Abstract:
1. A data encryption device which performs a predetermined encryption, based on a key, on a plain text and generates a ciphertext, said data encryption device comprising: a random number generation unit operable to generate a single first core random number, and to generate a first random number by concatenating a predetermined number of repetitions of the single first core random number; a plain text data-merging unit operable to perform an exclusive OR operation on the plain text and the first random number, and to generate intermediate data; and a data randomizing unit operable to perform a data randomizing process on the intermediate data for each round of the encryption, the data randomizing process being based on the first random number, a second random number which is a concatenation of repetitions of a second core random number, and the key, wherein said data randomizing unit includes: a transformation table storage unit operable to store only a single transformation table for transforming a number of data pieces for each round of the encryption, the number of the data pieces for each round of the encryption being equal to the predetermined number; a table modification unit operable to generate a single modified transformation table for each round of the encryption such that (i) an exclusive OR of input data to the single modified transformation table and the single first core random number is equal to the input data to the single transformation table and (ii) output data from the single modified transformation table is equal to an exclusive OR of output data from the single transformation table and the second core random number; a modified transformation table storage unit operable to store only the single modified transformation table; and a data transformation unit operable to perform a data transformation process, wherein the intermediate data for each round of the encryption is divided into a number of pieces equal to the predetermined number, and the data transformation process is performed on each of the number of pieces of the intermediate data for each round of the encryption based on the key and the single modified transformation table stored in said modified transformation table storage unit.