Abstract: According to one embodiment, a magnetic disk device includes a read and write channel transfers data to/from a magnetic disk; a data processor cancels an inter-track interference in data read; an encryption decode processor which is provided in common through a write data path and a read data path in the read and write channel and executes an encryption processing and a decode processing for the data to be transferred to/from the magnetic disk; and an encryption decode processing bypass module bypasses the encryption processing or the decode processing through the encryption decode processor in a cancellation of the inter-track interference in the data processor.

Abstract: According to one embodiment, there is provided an information storage apparatus, including: a plurality of nonvolatile memories configured to store encryption information so that the stored encryption information are read out therefrom; a plurality of encryption processing modules provided correspondingly with the respective memories, and configured to encrypt the information to be stored in the memories and to decrypt the encryption information read out from the memories; and a storage processing module configured to collectively store a plurality of key information that are utilized when the encryption processing modules encrypt the information to be stored or decrypt the encryption information read out.

Abstract: According to one embodiment, a magnetic disk device includes a read and write channel transfers data to/from a magnetic disk; a data processor cancels an inter-track interference in data read; an encryption decode processor which is provided in common through a write data path and a read data path in the read and write channel and executes an encryption processing and a decode processing for the data to be transferred to/from the magnetic disk; and an encryption decode processing bypass module bypasses the encryption processing or the decode processing through the encryption decode processor in a cancellation of the inter-track interference in the data processor.

Abstract: According to one embodiment, there is provided an information storage apparatus, including: a plurality of nonvolatile memories configured to store encryption information so that the stored encryption information are read out therefrom; a plurality of encryption processing modules provided correspondingly with the respective memories, and configured to encrypt the information to be stored in the memories and to decrypt the encryption information read out from the memories; and a storage processing module configured to collectively store a plurality of key information that are utilized when the encryption processing modules encrypt the information to be stored or decrypt the encryption information read out.

Abstract: According to one embodiment, a circuit includes: an ECC encoder to assign symbols of a data string to M interleaves in sequence, create redundancy symbols for each interleaved string, insert the redundancy symbol into the data string every N symbols of the data string, and create ECC encoded data, where M and N are greater than or equal to 2; and an ECC decoder to assign the symbols of the data string that has been inserted with the redundancy symbols to M interleaves and apply error correction to each assigned string, using the redundancy symbols of that assigned string. The encoder assigns each symbol of the data string that corresponds to an insertion position of the different one of the redundancy symbols in the data string to a next position next to and skipping an in-sequence interleaving position of that symbol, and creates the redundancy symbols for each interleaved string.

Abstract: According to one embodiment, an encryption device uses N extended keys (N: a natural number not less than 2) obtained by extending one encryption key, and includes a first memory, a comparison circuit, a second memory, a selector, and an extension calculator. The first memory stores a flag corresponding to an initial value of a key. The comparison circuit outputs a signal indicating comparison matching when a command and the key are related to encryption. The selector loads the key in the first memory into the second memory upon receiving the signal. The extension calculator calculates the extended keys based on the key in the second memory and inputs them to the selector. Except when loading the initial value of the key into the second memory, the selector loads the extended keys into the second memory to extend the encryption key to from the first to N-th extended keys.