Client-side boot domains and boot rules

• US 20050097328A1
• Filed: 12/16/2004
• Published: 05/05/2005
• Est. Priority Date: 12/10/1999
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: England, Paul
• Granted Patent: US 6,978,365 B2
• Time in Patent Office: Days
• US Class Current: 713/173
• CPC Class Codes: G06F 21/121 Restricting unauthorised execution of programs
• CPC Class Codes: G06F 21/33 using certificates
• CPC Class Codes: G06F 2211/1097 Boot, Start, Initialise, Power
• CPC Class Codes: G06F 9/4416 Network booting; Remote initial program loading [RIPL]

Abstract

Each software component loaded for a verified operating system on a client computer must satisfy a set of boot rules for a boot certificate. A verified operating system identifier is created from the boot certificate. The boot certificate is published and signed by a boot authority that attests to the validity of the operating system booted under the boot certificate. Each software component for the operating system is associated with a component certificate published and signed by the same boot authority that signed the boot certificate. The boot rules determine the validity of the software component based on the contents of the component and boot certificates. The client computer can transmit the verified operating system identity and the boot certificate to a server computer, such as a content provider, and the content provider can determine whether to trust the verified operating system with its content.

Claims

1. One or more computer-readable media having stored thereon instructions for establishing a boot domain on a client computer that, when executed by one or more processors, cause the one or more processors to:

select a boot certificate associated with the boot domain;

create a verified operating system identity from the boot certificate; and

load each one of a plurality of operating system components in accordance with a set of boot rules based on the boot certificate,

wherein each of the plurality of operating system components is associated with a component certificate and the set of boot rules comprises;

verifying that each component certificate is signed by a boot authority that issued the boot certificate;

verifying that each component certificate is valid as of an issue date for the boot certificate; and

verifying that each component is not listed in a revocation list associated with the boot certificate.

2. The one or more computer-readable media of claim 1, wherein the instructions further cause the one or more processors to:

obtain a new component certificate to replace a component certificate that is expired as of the issue date of the boot certificate.

3. The one or more computer-readable media of claim 1, wherein the instructions further cause the one or more processors to:

obtain a new component to replace a component that is listed in the revocation list associated with the boot certificate; and

obtain the associated component certificate for the new component.

4. One or more computer-readable media having stored thereon instructions for establishing a boot domain on a client computer that, when executed by one or more processors, cause the one or more processors to:

select a boot certificate associated with the boot domain;

create a verified operating system identity from the boot certificate;

load each one of a plurality of operating system components in accordance with a set of boot rules based on the boot certificate;

secure data for use in the boot domain using a key based on the verified identity of the operating system;

obtain a new boot certificate;

create a new verified operating system identity from the new boot certificate; and

re-secure the data in the boot domain with the new verified operating system identity.

5. The one or more computer-readable media of claim 4, wherein the instructions further cause the one or more processors to:

create an unverified operating system identity when one of the plurality of operating system components fails the set of boot rules.

6. The one or more computer-readable media of claim 4, wherein to re-secure the data in the boot domain is to:

verify that the new boot certificate is issued by a boot authority that is the same as the boot authority that issued the boot certificate;

verify that the new boot certificate is issued at a later date than the boot certificate;

verify that the data in the boot domain has not expired;

unseal the data in the boot domain with the verified operating system identity;

copy the data; and

seal the copy of the data with the new verified operating system identity.

7. The one or more computer-readable media of claim 4, wherein the actions are performed in the order recited.

8. A system for establishing a boot domain on a client computer comprising:

means for selecting a boot certificate associated with the boot domain;

means for creating a verified operating system identity from the boot certificate;

means for loading each one of a plurality of operating system components in accordance with a set of boot rules based on the boot certificate;

means for securing data for use in the boot domain using a key based on the verified identity of the operating system;

means for obtaining a new boot certificate;

means for creating a new verified operating system identity from the new boot certificate; and

means for re-securing the data in the boot domain with the new verified operating system identity.

9. The system of claim 8, further comprising:

means for creating an unverified operating system identity when one of the plurality of operating system components fails the set of boot rules.

10. The system of claim 8, wherein the means for re-securing the data in the boot domain comprises:

means for verifying that the new boot certificate is issued by a boot authority that is the same as the boot authority that issued the boot certificate;

means for verifying that the new boot certificate is issued at a later date than the boot certificate;

means for verifying that the data in the boot domain has not expired;

means for unsealing the data in the boot domain with the verified operating system identity;

means for copying the data; and

means for sealing the copy of the data with the new verified operating system identity.