US Patent 7627756 Storage system for data encryption

Provided is a storage system including: a host interface connected via a network to a host computer; a disk interface connected to a disk drive; a memory module that stores control information of a cache memory for an access to the disk drive and the storage system; a processor that controls the storage system; a mature network that interconnects the host interface, the disk interface, the memory module, and the processor; and an encryption module that encrypts data read/written by the host computer, in which the processor reads data from a given area of the disk drive from the memory module, decrypts the read data with an encryption key corresponding to this data, encrypts the decrypted data with an encryption key different from the one that has just been used to decrypt the data, and writes the encrypted data in an area different from the given area. Accordingly, customers can be provided with a secure, highly reliable storage system with its confidentiality preserving capability enhanced.