Ciphered data storage device

TL;DR: In this article, the authors proposed to use a cache to reduce the number of accesses to a flash memory for recording unit data including secondary information to be annexed to a data body required to be protected.

Abstract: PROBLEM TO BE SOLVED: To reduce the number of accesses to a flash memory for recording unit data including secondary information to be annexed to a data body required to be protected and the number of times of calculation of an ICV. SOLUTION: In addition to a data ciphering/deciphering unit 11, a hard disk 15 for recording ciphered data and a flash memory 20 for recording ciphered unit data including secondary information annexed to the data body stored in the hard disk 15 together with the ICV, a ciphered data storage device is provided with a cache device 16 including a cache memory 17 whose access speed is faster than the flash memory 20. The ciphered unit data to be recorded in the cache memory 17 can be grouped in accordance with the type or the like of the data and managed by a cache optimizing device 18 so as to preferentially leave unit data whose reference frequency is high or unit data which are recently updated.