摘要 |
A data encryption device performs high-speed access to an arbitrary page when encrypting data and writing it to a storage device that can be accessed in a page unit or reading data therefrom and decrypting it. The device: encrypts data and writes it to the storage device or reads data from the storage device and decrypts it by a stream cipher; uses a counter mode of a block cipher to generate pseudorandom number series; specifies a data position in the storage device based on a page number and a page block number, by dividing one page into plural page blocks having a block length of the block cipher; and uses a value determined by a function of the page number, the page block number, and an arbitrary offset value, as an initial value of a pseudorandom number to be used in the counter mode.
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