System and Method for Authenticating an Operating System to a Central Processing Unit, Providing the CPU/OS with Secure Storage, and Authenticating the CPU/OS to a Third Party

• US 20070104329A1
• Filed: 12/22/2006
• Published: 05/10/2007
• Est. Priority Date: 10/26/1998
• Status: Abandoned Application

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: England, Paul, Lampson, Butler, Detreville, John
• Application Number:
  US11/615,195
• Publication Number:
  US 20070104329A1
• Time in Patent Office: Days
• US Class Current: 380/255
• CPC Class Codes: G06F 21/1011 to devices
• CPC Class Codes: G06F 21/445 by mutual authentication, e.g. between devices or programs
• CPC Class Codes: G06F 21/57 Certifying or maintaining trusted computer platforms, e.g. secure boots or power-downs, version controls, system software checks, secure updates or assessing vulnerabilities
• CPC Class Codes: G06F 21/575 Secure boot
• CPC Class Codes: G06F 2221/2103 Challenge-response
• CPC Class Codes: G06F 2221/2113 Multi-level security, e.g. mandatory access control
• CPC Class Codes: G06F 2221/2129 Authenticate client device independently of the user
• CPC Class Codes: G06F 9/4406 Loading of operating system
• CPC Class Codes: G06F 9/468 Specific access rights for resources, e.g. using capability register

Abstract

In accordance with certain aspects, an operating system is booted for execution on a central processing unit (CPU). An atomic operation is executed, and if the atomic operation completes correctly then a software identity register of the CPU is set to an identity of the operating system.

Claims

1. In a computer system having a central processing unit (CPU) and an operating system (OS), the CPU having a software identity register, a method for booting the operating system comprising:

computing a cryptographic function of at least a portion of the operating system; and

setting the software identity register to a result of the computed cryptographic function if atomic execution of a boot block of the operating system does not fail, and otherwise setting the software identity register to a value indicating that the atomic execution of the boot block failed.

2. The method as recited in claim 1, further comprising defining a secure storage space, access to which is based in part on the result set in the software identity register.

3. A computer comprising:

a memory;

a central processing unit (CPU) coupled to the memory, the CPU having a software identity register;

an operating system stored in the memory, the operating system having a block of code; and

the operating system being booted for execution on the CPU according to a sequence that begins with an atomic operation, wherein in an event that the atomic operation completes correctly, the software identity register is set to the identity of the operating system.

4. The computer as recited in claim 3, wherein the identity comprises a digital signature on a block of code from the operating system.

5. The computer as recited in claim 3, wherein the identity comprises a hash digest of a block of code from the operating system.

6. The computer as recited in claim 3, wherein the CPU holds a manufacturer certificate signed by a manufacturer of the CPU.

7. The computer as recited in claim 3, further comprising a boot log, wherein the CPU appends the identity of the operating system to the boot log in the event that the atomic operation completes correctly.

8. The computer as recited in claim 3, wherein the CPU is assigned a pair of public and private keys, and CPU is configured to create an OS certificate containing the identity in the software identity register, information describing the operating system, and the CPU public key, the CPU signing the OS certificate using the CPU private key.

9. The computer as recited in claim 3, wherein the CPU is configured to form a generator seed from a CPU-specific secret and OS-specific data and to generate a private storage key based on a function of the generator seed.

10. A central processing unit comprising:

software identity register;

a boot log; and

processing means to process an atomic operation such that in an event that the atomic operation completes correctly, the software identity register is set to an identity of software code and the identity is appended to the boot log.

11. For execution on a computer system having a central processing unit (CPU) and an operating system (OS), the CPU having a software identity register, a computer program stored on one or more computer-readable storage media of the computer system, the program comprising:

executing an atomic operation to set an identity of the operating system into the software identity register of the CPU, wherein in an event that the atomic operation completes correctly, the software identity register contains the identity of the operating system and in an event that the atomic operation fails to complete correctly, the software identity register contains a value other than the identity of the operating system; and

examining a content of the software identity register to verify the identity of the operating system.