Secure memory card with life cycle phases

• US 8,423,788 B2
• Filed: 02/07/2005
• Issued: 04/16/2013
• Est. Priority Date: 02/07/2005
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Inventors: Holtzman, Micky, Cohen, Baruch Boris, Barzilai, Ron
• Primary Examiner(s): Zand, Kambiz
• Assistant Examiner(s): Hailu, Teshome
• Application Number:
  US11/053,273
• Publication Number:
  US 20060177064A1
• Time in Patent Office: 2,990 Days
• Field of Search: 713/189, 380/277, 711/164, 711/163
• US Class Current: 713/189
• CPC Class Codes: G06F 21/77 in smart cards
• CPC Class Codes: G06F 2221/2105 Dual mode as a secondary aspect
• CPC Class Codes: G06F 2221/2143 Clearing memory, e.g. to prevent the data from being stolen
• CPC Class Codes: H04L 2209/12 Details relating to cryptographic hardware or logic circuitry
• CPC Class Codes: H04L 2209/26 Testing cryptographic entity, e.g. testing integrity of encryption key or encryption algorithm
• CPC Class Codes: H04L 9/0897 involving additional devices, e.g. trusted platform module [TPM], smartcard or USB

Abstract

A secure memory card with encryption capabilities comprises various life cycle states that allow for testing of the hardware and software of the card in certain of the states. The testing mechanisms are disabled in certain other of the states thus closing potential back doors to secure data and cryptographic keys. Controlled availability and generation of the keys required for encryption and decryption of data is such that even if back doors are accessed that previously encrypted data is impossible to decrypt and thus worthless even if a back door is found and maliciously pried open.

Claims

1. A memory card having a plurality of states which may be entered sequentially, wherein the memory card is operable either as a secure card in one state or as a non-secure card in a subsequent state, the memory card comprising:

a non-volatile memory; and

a controller coupled to the non-volatile memory and including a cryptographic function,

wherein the controller is configured to transition the memory card between a testing state in which testing of the memory card is enabled, a secure operating state in which the cryptographic function is enabled and the memory card is operational for use as a secure card, and, after operating in the secure operating state, a bypass state in which the cryptographic function is disabled and the memory card is operational as a non-secure card, and wherein once in the bypass state the controller operates the memory card as a non-secure card wherein the memory card is unable to ever again transition to the secure operating state.

2. The memory card of claim 1, wherein the memory card is configured for deployment in the bypass state as the non-secure card.

3. The memory card of claim 1, wherein the memory card is configured for deployment in the secure operating state as the secure card.

4. The memory card of claim 3, wherein the memory card is initially configured for deployment as the secure card and is reconfigurable upon return to a manufacturer as the non-secure card via the bypass state of the controller.

5. The memory card of claim 1, wherein the memory card is configured to operate only one state at a time.

6. The memory card of claim 5, wherein the controller is further configured to transition to a failure analysis state from the secure operating state and to prevent the controller from re-entering the secure operating state.

7. A method of operating a memory card either as a secure card or as a non-secure card, comprising:

in a memory card having a non-volatile memory, a controller coupled to the non-volatile memory and including a cryptographic function, the memory card;

entering into a testing state in which testing of the memory card is enabled;

entering into a secure operating state after the testing state wherein the cryptographic function is enabled and the memory card is operational as a secure card; and

entering into a bypass state after the secure operating state, wherein the cryptographic function is disabled, the memory card is operational as a non-secure card and once in the bypass state the controller operates the memory card as a non-secure card wherein the memory card is unable to ever again transition to the secure operating state.