MRAM-based security for data storage systems

• US 8,909,942 B1
• Filed: 03/30/2012
• Issued: 12/09/2014
• Est. Priority Date: 03/30/2012
• Status: Active Grant

• Current Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: Latifi, Afshin, Jones, Justin, Obukhov, Dmitry S.
• Primary Examiner(s): Mehedi, Morshed
• Assistant Examiner(s): Lynch, Sharon
• Application Number:
  US13/436,327
• Time in Patent Office: 984 Days
• Field of Search: 380/277, 713/193
• US Class Current: 713/193
• CPC Class Codes: G06F 12/1408 by using cryptography for digital transmission H04L9/00
• CPC Class Codes: G06F 21/60 Protecting data
• CPC Class Codes: G06F 21/78 to assure secure storage of data address-based protection against unauthorised use of memory G06F12/14; record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: G06F 2212/2024 Rewritable memory not requiring erasing, e.g. resistive or ferroelectric RAM
• CPC Class Codes: G06F 2221/2143 Clearing memory, e.g. to prevent the data from being stolen
• CPC Class Codes: G11C 11/1695 Protection circuits or methods

Abstract

A secure data storage system includes a mechanism that can be activated to inhibit access to stored data. In one embodiment, access to stored data can be prevented without having to erase or modify such data. An encryption key, or data used to generate the encryption key, is stored in an MRAM module integrated within the data storage system. The data storage system uses the encryption key to encrypt data received from a host system, and to decrypt the encrypted data when it is subsequently read by a host system. To render the stored data inaccessible, an operator (or an automated process) can expose the MRAM module to a magnetic field of sufficient strength to erase key data therefrom.

Claims

1. A data storage system, comprising:

a non-volatile memory array;

a magnetoresistive random access memory (MRAM) module configured to store key data, the MRAM module configured to store the key data without application of a bias magnetic field and not physically enclosed in a shielding configured to shield the MRAM module from a non-bias magnetic field that renders inaccessible data stored in the MRAM module, the non-bias magnetic field configured to be applied in response to a vendor specific command received from a host system, the key data configured to be;

accessible when the non-bias magnetic field is not applied to the MRAM module, and

rendered inaccessible when the non-bias magnetic field is applied to the MRAM module,

wherein the MRAM module remains stationary relative to the data storage system during application of the non-bias magnetic field, and

wherein when the data storage system has failed, replacement key data is generated by computing an error correction code and an authentication value; and

data protector circuitry configured to;

use the key data stored in the MRAM module to encrypt data received from the host system for storage in the memory array; and

use the key data stored in the MRAM module to decrypt encrypted data read from the memory array,

wherein application of the non-bias magnetic field

     1) disables the ability of the data protector circuitry to decrypt encrypted data stored in the memory array,

     2) prevents access to data stored in the memory array without erasing any of data stored in the memory array, and

     3) renders the key data stored in the MRAM module inaccessible even after the data storage system has failed.

2. The data storage system of claim 1, further comprising a magnetic field generator configured to, when powered, generate the non-bias magnetic field configured to render inaccessible data stored in the MRAM module.

3. The data storage system of claim 1, wherein the memory array comprises solid-state memory.

4. The data storage system of claim 1, wherein the data storage system comprises one of:

a solid-state drive or a hybrid hard drive.

5. The data storage system of claim 1, wherein the key data comprises a key used to encrypt and decrypt data.

6. The data storage system of claim 1, wherein the data protector circuitry is further configured to generate a key based at least in part on the key data, the key used to encrypt and decrypt data.

7. The data storage system of claim 1, wherein the data protector circuitry is configured to encrypt the data and decrypt the encrypted data without sharing the key data with the host system.

8. A method of securely storing data in a data storage system, the method comprising:

accessing key data stored in a magnetoresistive random access memory (MRAM) module, the MRAM module storing the key data without application of a bias magnetic field and not physically enclosed in a shielding configured to shield the MRAM module from a non-bias magnetic field that renders inaccessible the key data, the non-bias magnetic field applied in response to a vendor specific command received from a host system;

generating a key based at least in part on the key data;

encrypting data received from the host system using the generated key;

storing the encrypted data in a non-volatile memory array;

decrypting the encrypted data stored in the memory array using the key; and

providing the decrypted data to the host system, wherein the key is required to decrypt the encrypted data stored in the memory array,

wherein exposing the MRAM module to the non-bias magnetic field

     1) disables the functionality of decrypting the encrypted data stored in the memory array,

     2) prevents access to data stored in the memory array without erasing any of data stored in the memory array, and

     3) renders the key data inaccessible even after the data storage system has failed,

wherein the MRAM module remains stationary relative to the data storage system during application of the non-bias magnetic field,

wherein when the data storage system has failed, replacement key data is generated by computing an error correction code and an authentication value, and

wherein the method is performed under the control of a controller.

9. The method of claim 8, further comprising encrypting data and decrypting the encrypted data without sharing the key with the host system.

14. The data storage system of claim 9, wherein the controller is configured to encrypt the data and decrypt the encrypted data without sharing the key with the host system.

10. A data storage system comprising:

a non-volatile memory array configured to store data communicated by a host system;

a magnetoresistive random access memory (MRAM) module configured to store key data, wherein the MRAM module is configured to store the key data without application of a bias magnetic field and not physically enclosed in a shielding configured to shield the MRAM module from a non-bias magnetic field that renders inaccessible data stored in the MRAM module, the non-bias magnetic field configured to be applied in response to a vendor specific command received from the host system, the key data configured to be;

accessible when the non-bias magnetic field is not applied to the MRAM module, and

rendered inaccessible when the non-bias magnetic field is applied to the MRAM module,

wherein the MRAM module remains stationary with respect to the data storage system during application of the non-bias magnetic field, and

wherein when the data storage system has failed, replacement key data is generated by computing an error correction code and an authentication value; and

a controller configured to;

generate a key based at least in part on the key data stored in the MRAM module;

in response to receiving a write command from the host system comprising data, encrypt the data using the key and store the encrypted data in the memory array;

in response to receiving a read command from the host system to retrieve the data, decrypt the encrypted data using the key and provide the decrypted data to the host system,

wherein the key is required to decrypt the encrypted data stored in the memory array, and

wherein application of the non-bias magnetic field

     1) disables the ability of the controller to decrypt the encrypted data stored in the memory array,

     2) prevents access to data stored in the memory array without erasing any of data stored in the memory array, and

     3) renders the key data stored in the MRAM module inaccessible even after the data storage system has failed.

11. The data storage system of claim 10, wherein the controller is further configured to:

in response to receiving the vendor specific command from the host system, render inaccessible the key data stored in the MRAM module, thereby preventing decryption of the encrypted data stored in the memory array.

12. The data storage system of claim 10, further comprising an anti-tampering label configured to indicate whether the data storage system was tampered with.

13. The data storage system of claim 12, wherein the anti-tampering label is configured to be affixed to at least a part of the MRAM module in order to indicate whether the MRAM module or an interface between the MRAM module and the controller were tampered with.

15. A method of securely storing data in a data storage system, the method comprising:

accessing key data stored in a magnetoresistive random access (MRAM) module, the MRAM module storing the key data without application of a bias magnetic field and not physically enclosed in a shielding configured to shield the MRAM module from a non-bias magnetic field that renders inaccessible data stored in the MRAM module, the non-bias magnetic field applied in response to a vendor specific command received from a host system;

in response to determining that the key data is not successfully accessed, generating a replacement key data and storing the replacement key data in the MRAM module;

generating a key based on the key data or the replacement key data; and

using the key, encrypting data for storing in a non-volatile memory array and decrypting data retrieved from the memory array,

wherein application of the non-bias magnetic field

     1) disables the functionality of decrypting data stored in the memory array,

     2) prevents access to data stored in the memory array without erasing any of data stored in the memory array,

     3) renders the key data or replacement key data stored in the MRAM module inaccessible even when the data storage system has become nonfunctional,

wherein the MRAM module remains stationary with respect to the data storage system during application of the non-bias magnetic field,

wherein when the data storage system has failed, the replacement key data is generated by computing an error correction code and an authentication value, and

wherein the method is performed under the control of a controller.

16. The method of claim 15, wherein accessing the value stored in the MRAM module is performed during start-up of the data storage system.

17. The method of claim 15, further comprising encrypting data and decrypting the encrypted data without sharing the key with the host system.