SECURE PROCESSOR ARCHITECTURE FOR USE WITH A DIGITAL RIGHTS MANAGEMENT (DRM) SYSTEM ON A COMPUTING DEVICE

• US 20070226492A1
• Filed: 05/29/2007
• Published: 09/27/2007
• Est. Priority Date: 03/27/1999
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: England, Paul, Peinado, Marcus
• Granted Patent: US 8,065,521 B2
• Time in Patent Office: Days
• US Class Current: 713/164
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 21/71 to assure secure computing or processing of information
• CPC Class Codes: G06F 2221/2105 Dual mode as a secondary aspect
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• CPC Class Codes: H04L 63/068 using time-dependent keys, e.g. periodically changing keys cryptographic mechanisms or cryptographic arrangements for controlling usage of secret information H04L9/088
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 63/12 Applying verification of the received information cryptographic mechanisms or cryptographic arrangements for data integrity or data verification H04L9/32
• CPC Class Codes: H04L 9/0897 involving additional devices, e.g. trusted platform module [TPM], smartcard or USB
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions
• CPC Class Codes: H04L 9/3263 involving certificates, e.g. public key certificate [PKC] or attribute certificate [AC]; Public key infrastructure [PKI] arrangements network architectures or network communication protocols for supporting authentication of entities using certificates in a packet data network H04L63/0823

Abstract

A secure processor is operable in normal and preferred modes, and includes a security kernel instantiated when the processor enters into preferred mode and a security key accessible by the security kernel during preferred mode. The security kernel employs the accessed security key to authenticate a secure application, and allows the processor to be trusted to keep hidden a secret of the application. To instantiate the application, the processor enters preferred mode where the security key is accessible, and instantiates and runs the security kernel. The security kernel accesses the security key and applies same to decrypt a key for the application, stores the decrypted key in a location where the application will expect same, and instantiates the application. The processor then enters the normal mode, where the security key is not accessible.

Claims

1. A secure processor for a computing device, the processor being operable in a normal mode and a preferred mode, the processor including a security kernel for being instantiated on the processor when the processor enters into the preferred mode and a security key accessible by the instantiated security kernel when the processor is operating in the preferred mode, the security kernel employing the accessed security key during the preferred mode to authenticate a secure application on the computing device, wherein the security kernel allows the processor to be trusted to keep hidden a secret of the application.

2. The processor of claim 1 in combination with the application.

3. The processor of claim 2 wherein the application is selected from a group consisting of a digital rights management (DRM) system and a banking/financial system.

4. The processor of claim 1 wherein the security kernel automatically authenticates a particular application.

5. The processor of claim 1 wherein the security kernel initially authenticates a chooser application that allows a user to select from at least one available applications on the computing device.

6. The processor of claim 1 wherein the security kernel employs the accessed security key during the preferred mode to decrypt at least one encrypted key for the application.

7. The processor of claim 1 in combination with the computing device.

8. The processor of claim 7 wherein the computing device is a portable computing device.

9. The processor of claim 1 further comprising a storage space, the security kernel being permanently stored in the storage space.

10. The processor of claim 1 further comprising a storage space, the security key being permanently stored in the storage space.

11. The processor of claim 1 wherein the security kernel employs the accessed security key during the preferred mode to authenticate/verify the application prior to instantiation thereof.

12. The processor of claim 11 wherein the security kernel performs a hash/MAC (message authentication code) over at least a portion of the application and then compares the hash/MAC to a hash/MAC corresponding to the application.

13. The processor of claim 1 wherein such processor enters preferred mode whenever a predefined initializing processor action is performed.

14. The processor of claim 13 wherein such processor enters preferred mode whenever a CPU reset is performed.

15. A method for a secure processor to instantiate a secure application thereon, the method comprising:

instantiating a first security kernel which employs symmetric cryptography;

instantiating by way of the instantiated first security kernel a second security kernel which employs asymmetric cryptography; and

authenticating by way of the instantiated second security kernel the secure application.

16. The method of claim 15 wherein the security key of the processor is a symmetric key and the second security kernel is instantiated by the first security kernel from a code image including a main body and a header including:

KCPU (KMAN) KMAN encrypted according to KCPU KMAN (KCODE) KCODE encrypted according to KMAN

where KCPU is a security key of the processor, KMAN is a device key independent of the security key, and KCODE is the private key of the second security kernel, and

wherein the first security kernel applies the security key to decrypt the private key of the second security kernel during instantiation thereof by;

applying KCPU to KCPU (KMAN) to produce KMAN; and

applying KMAN to KMAN (KCODE) to produce KCODE.

17. The method of claim 15 wherein the application is instantiated by the second security kernel from a code image including a main body and a header including:

public key (KCODE) KCODE encrypted according to the public key

where KCODE is the secret of the application, and

wherein the second security kernel applies the private key to decrypt the secret of the application during authentication thereof.

18. A computer-readable medium having stored thereon computer-executable instructions implementing a method for a secure processor to instantiate a secure application thereon, the method comprising:

instantiating a first security kernel which employs symmetric cryptography;

instantiating by way of the instantiated first security kernel a second security kernel which employs asymmetric cryptography; and

authenticating by way of the instantiated second security kernel the secure application.

19. The medium of claim 18 wherein the security key of the processor is a symmetric key and the second security kernel is instantiated by the first security kernel from a code image including a main body and a header including:

KCPU (KMAN) KMAN encrypted according to KCPU KMAN (KCODE) KCODE encrypted according to KMAN

where KCPU is a security key of the processor, KMAN is a device key independent of the security key, and KCODE is the private key of the second security kernel, and

wherein the first security kernel applies the security key to decrypt the private key of the second security kernel during instantiation thereof by;

applying KCPU to KCPU (KMAN) to produce KMAN; and

applying KMAN to KMAN (KCODE) to produce KCODE.

20. The medium of claim 18 wherein the application is instantiated by the second security kernel from a code image including a main body and a header including:

public key (KCODE) KCODE encrypted according to the public key

where KCODE is the secret of the application, and

wherein the second security kernel applies the private key to decrypt the secret of the application during instantiation thereof.