Saving encryption keys in one-time programmable memory

• US 8,286,004 B2
• Filed: 04/27/2010
• Issued: 10/09/2012
• Est. Priority Date: 10/09/2009
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: LSI Corporation (Broadcom, Inc.)
• Inventors: Williams, Jeffrey L.
• Primary Examiner(s): Dada, Beemnet
• Application Number:
  US12/767,985
• Publication Number:
  US 20110087898A1
• Time in Patent Office: 896 Days
• Field of Search: 713/162, 713/164, 713/165, 713/189, 713/190, 713/193, 380/44, 380/46, 380/278
• US Class Current: 713/193
• CPC Class Codes: G06F 21/31 User authentication
• 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: H04L 2209/12 Details relating to cryptographic hardware or logic circuitry
• CPC Class Codes: H04L 9/0866 involving user or device identifiers, e.g. serial number, physical or biometrical information, DNA, hand-signature or measurable physical characteristics
• CPC Class Codes: H04L 9/3226 using a predetermined code, e.g. password, passphrase or PIN network architectures or network communication protocols for supporting authentication of entities using passwords in a packet data network H04L63/083
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions

Abstract

Described embodiments provide encryption/decryption of data transferred between a media controller and a storage device. The media controller provides encryption/decryption based on a root key (RK). Storage in a one-time programmable (OTP) memory is provided as a plurality of un-burned slots. The OTP memory is initially provided without the RK, which is generated with a random number generator. A control module performs the steps of i) burning the RK to an initial slot of the OTP memory, and ii) validating the burned RK (bRK) stored at the initial slot based on a comparison of the RK and the burned RK. If the control module validates the burned RK, the burned RK is employed by the media controller. Otherwise, one or more subsequent slots of the OTP memory are burned with the RK until the control module validates the corresponding burned RK.

Claims

1. A method of providing encryption/decryption of data transferred between a media controller and a storage device, wherein the media controller providing said encryption/decryption based on a root key (RK), the method comprising:

providing storage in a one-time programmable (OTP) memory as a plurality of un-burned slots to store data, the OTP memory initially provided without the RK;

generating, with a random number generator, the RK;

performing, with a control module, the steps of i) burning the RK to an initial slot of the OTP memory, and ii) validating the burned RK (bRK) stored at the initial slot based on a comparison of the RK and the burned RK;

wherein, when the control module validates the burned RK;

employing the burned RK as the RK by the media controller to provide said encryption/decryption;

otherwise;

burning one or more subsequent slots with the RK and validating each corresponding bRK until the control module validates the corresponding burned RK, and then employing the burned RK as the RK by the media controller to provide said encryption/decryption;

wherein the comparison of the RK and the burned RK (bRK) is based on a maximum threshold of changed bits; and

wherein a number of changed bits between RK and the bRK is determined by an exclusive-or (XOR) operation.

2. The method of claim 1, further comprising:

burning a checksum (cbRK) of the burned RK to the corresponding slot of OTP memory.

3. The method of claim 1, further comprising:

if the control module validates the burned RK;

employing the burned RK as the RK by the media controller to provide said encryption/decryption;

otherwise;

burning one or more subsequent slots with the RK and validating each corresponding bRK until either i) the control module validates the corresponding burned RK, and then employing the burned RK as the RK by the media controller to provide said encryption/decryption, or ii) all slots of the OTP memory are used.

4. The method of claim 2, further comprising:

comparing, by a comparator, the checksum of the burned RK (cbRK) and a value, read from the OTP memory, of the checksum of the burned RK (rcbRK);

wherein, if the cbRK and the rcbRK are substantially equal;

employing the burned RK as the RK by the media controller to provide said encryption/decryption;

otherwise;

burning one or more subsequent slots with the RK and validating each corresponding bRK until the control module validates the corresponding burned RK, and then employing the burned RK as the RK by the media controller to provide said encryption/decryption.

5. A non-transitory machine-readable storage medium, having encoded thereon program code, wherein, when the program code is executed by a machine, the machine implements a method of providing encryption/decryption of data transferred between a media controller and a storage device, wherein the media controller providing said encryption/decryption based on a root key (RK), the method comprising:

providing storage in a one-time programmable (OTP) memory as a plurality of un-burned slots to store data, the OTP memory initially provided without the RK;

generating, with a random number generator, the RK;

performing, with a control module, the steps of i) burning the RK to an initial slot of the OTP memory, and ii) validating the burned RK (bRK) stored at the initial slot based on a comparison of the RK and the burned RK;

wherein, when the control module validates the burned RK;

employing the burned RK as the RK by the media controller to provide said encryption/decryption;

otherwise;

burning one or more subsequent slots with the RK and validating each corresponding bRK until the control module validates the corresponding burned RK, and then employing the burned RK as the RK by the media controller to provide said encryption/decryption;

wherein the comparison of the RK and the burned RK (bRK) is based on a maximum threshold of changed bits; and

wherein a number of changed bits between RK and the bRK is determined by an exclusive-or (XOR) operation.

6. The computer readable medium of claim 5, further comprising:

burning a checksum (cbRK) of the burned RK to the corresponding slot of OTP memory.

7. The computer readable medium of claim 5, further comprising:

if the control module validates the burned RK;

employing the burned RK as the RK by the media controller to provide said encryption/decryption;

otherwise;

burning one or more subsequent slots with the RK and validating each corresponding bRK until either i) the control module validates the corresponding burned RK, and then employing the burned RK as the RK by the media controller to provide said encryption/decryption, or ii) all slots of the OTP memory are used.

8. The computer readable medium of claim 6, further comprising:

comparing, by a comparator, the checksum of the burned RK (cbRK) and a value, read from the OTP memory, of the checksum of the burned RK (rcbRK);

wherein, if the cbRK and the rcbRK are substantially equal;

employing the burned RK as the RK by the media controller to provide said encryption/decryption;

otherwise;

burning one or more subsequent slots with the RK and validating each corresponding bRK until the control module validates the corresponding burned RK, and then employing the burned RK as the RK by the media controller to provide said encryption/decryption.

9. An apparatus comprising a media controller configured to provide encryption/decryption of data transferred between the media controller and a storage device, wherein the media controller provides said encryption/decryption based on a root key (RK), the apparatus comprising:

a one-time programmable (OTP) memory having a plurality of un-burned slots to store data, wherein the OTP memory is initially provided without the RK;

a random number generator configured to generate the RK;

a control module configured to i) burn the RK to an initial slot of the OTP memory, and ii) validate the burned RK (bRK) stored at the initial slot based on a comparison of the RK and the burned RK,

wherein, when the control module validates the burned RK;

the burned RK is employed as the RK by the media controller to provide said encryption/decryption;

otherwise;

the control module is configured to burn one or more subsequent slots with the RK and validate each corresponding bRK until the control module validates the corresponding burned RK, the burned RK employed as the RK by the media controller to provide said encryption/decryption;

wherein the comparison of the RK and the burned RK (bRK) is based on a maximum threshold of changed bits; and

wherein a number of changed bits between RK and the bRK is determined by an exclusive-or (XOR) operation.

10. The apparatus of claim 9, wherein the control module is adapted to burn a checksum (cbRK) of the burned RK to the corresponding slot of OTP memory.

11. The apparatus of claim 9, wherein the control module is configured to burn one or more subsequent slots with the RK and validate each corresponding bRK until either i) the control module validates the corresponding burned RK, and then employing the burned RK as the RK by the media controller to provide said encryption/decryption, or ii) all slots of the OTP memory are used.

12. The apparatus of claim 9, wherein the comparator is adapted to compare a checksum of the burned RK (cbRK) and a value, read from the OTP memory, of the checksum of the burned RK (rcbRK), wherein

if the cbRK and the rcbRK are substantially equal, the burned RK is employed as the RK by the media controller to provide said encryption/decryption;

otherwise;

one or more subsequent slots are burned with the RK until the control module validates the corresponding burned RK, and then employing the burned RK as the RK by the media controller to provide said encryption/decryption.

13. The apparatus of claim 9, wherein the apparatus is implemented in a monolithic integrated circuit chip.