Storage apparatus and data writing method

A data writing method applied to a storage apparatus including a controller and a key changing module, the controller being configured to encrypt user data with a key, and write the encrypted user data in a storage medium, the key changing module being configured to change the key, the storage medium including a user data region storing the encrypted user data and a key changing region of a logical block with a predetermined size, the key changing region being adjacent to the user data region, the data writing method comprising:

• when the key is changed, the controller of the storage apparatus dividing the user data written in the storage medium into a plurality of pieces of the user data each corresponding to a logical block size of the logical block, encrypting a piece of the user data adjacent to the key changing region with the changed key, writing the encrypted piece into the key changing region, sequentially shifting each of the pieces of the user data other than the piece of the user data adjacent to the key changing region by one logical block size in a direction toward the key changing region from positions in the storage region in which the pieces of the divided user data other than the piece of the divided user data adjacent to the key changing region are written, and writing the shifted pieces.