Patent ID: 8555084
Filing Date: 2013-10-08
Classification: G06F,H04L

Abstract:
1. A data encryption device that encrypts data to be stored in a storage device by a stream cipher and writes the encrypted data to the storage device, or reads the encrypted data from the storage device and decrypts the read data by the stream cipher, the storage device being accessed in a page unit, and uses a counter mode of a block cipher to generate pseudorandom numbers for encryption or decryption, wherein the page is divided into a plurality of page blocks that have the same block length as a block length of the block cipher, and encryption or decryption is performed in a counter mode of the block cipher in the divided page block unit, a position of the data to be written or read in the page is specified by a page block number of each of the page blocks, and a value obtained by a function of a page number and the page block number of the page to be written or read, and an offset value which is constant in encryption or decryption but different for each data encryption device is used as an initial value for generating each of the pseudorandom numbers.