US 9,311,256 B2Granted

Storage device

AssigneeKabushiki Kaisha Toshiba

InventorsYoshiyuki Kudoh, Yasuto Aramaki, Taichiro Yamanaka, Hiroki Udagawa

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Abstract

A storage device includes a non-volatile memory having a plurality of storage areas. Received data is encrypted with a first cryptographic key and stored in one of the storage areas. Upon receiving an request from a host, a key processor replaces the first cryptographic key used to encrypt data stored on a specified one of the non-volatile memories with a different cryptographic key not previously used for any of the storage areas by generating a second cryptographic key, converting the previously used keys into first value by an operation, converting the candidate key into a second value by the same operation. The first and second values are compared, and when the first information is not the same as the second information, the second cryptographic key replaces the first cryptographic key, and when not, the second cryptographic key is discarded and a new second cryptographic key generated.

Claims8

Dependent claims

A storage device comprising:

a cipher processor that receives data from a host and encrypts the data received from the host using a first cryptographic key;
a first non-volatile memory that stores the data encrypted by the cipher processor;
and
a key processor that replaces a first cryptographic key having been used by the cipher processor with a cryptographic key that is different from the first cryptographic key according to a request from the host,
wherein the key processor comprises:
a key generator that generates a second cryptographic key;
a history manager that converts the first cryptographic key and past cryptographic keys previously used to encrypt received data into first information by an operation and stores the first information, said operation having a property of converting the same two input values into the same output values respectively and two different input values into output values different from each other;
a converter processor that converts the second cryptographic key into second information by the same operation used to convert the first cryptographic key and the past cryptographic keys into said first information;
and
a comparator that reads out the first information from the history manager, compares the read-out first information and the second information, and when the read-out first information and the second information have different values, replaces the first cryptographic key with the second cryptographic key and when the read-out first information and the second information have the same values, discards the second cryptographic key and generates a new second cryptographic key,
wherein the first non-volatile memory comprises a plurality of storage areas,
wherein the cipher processor uses a different cryptographic key for each of the plurality of storage areas, and
wherein the request specifies one of the plurality of storage areas.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/475,936Filed 3 Sep 2014 · us provisional application
Priority: 9 Jun 2014
Published: US 2015/0356028 A110 Dec 2015
Granted: 12 Apr 2016
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G06F 12/1408
Protection against unauthorised use of memory or access to memory: by using cryptography
H04L 9/0894
Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords: escrow, recovery or storing of secret…
G06F 2212/1052
Providing a specific technical effect: security improvement
G06F
Computing and data processing