Trust-Management Systems and Methods

• US 20110238982A1
• Filed: 03/29/2011
• Published: 09/29/2011
• Est. Priority Date: 05/19/2000
• Status: Active Grant

• Current Assignee: Intertrust Technologies Corporation (Fidelio Acquisition Co LLC)
• Original Assignee: Intertrust Technologies Corporation (Fidelio Acquisition Co LLC)
• Inventors: Serret-Avila, Xavier, Weeks, Stephen P.
• Granted Patent: US 8,578,151 B2
• Time in Patent Office: Days
• US Class Current: 713/156
• CPC Class Codes: G06F 21/604 Tools and structures for managing or administering access control systems
• CPC Class Codes: G06F 2221/2141 Access rights, e.g. capability lists, access control lists, access tables, access matrices
• 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

The present invention provides systems and methods for making efficient trust management decisions. A trust management engine is provided that processes requests for system resources, authorizations or certificates, and the identity of one or more root authorities that are ultimately responsible for granting or denying the requests. To determine whether a request should be granted, the trust management engine identifies a set principals from whom authorization may flow, and interprets each of the certificates as a function of the state of one or more of the principals. The processing logic iteratively evaluates the functions represented by the certificates, updates the states of the principals, and repeats this process until a reliable determination can be made as to whether the request should be granted or denied. The certificates may be evaluated until the state of the root authority indicates that the request should be granted, or until further evaluation of the certificates is ineffective in changing the state of the principals.

Claims

1. A system for controlling access to electronic resources, the system comprising:

a first computer system for processing requests for system resources, the first computer system comprising;

a network interface for receiving digital certificates from other systems and for receiving requests to access electronic resources;

a memory for storing electronic resources and one or more certificates relating thereto; and

a trust management engine for processing digital certificates and requests for electronic resources, and for making access control decisions by performing least fixpoint computations using said digital certificates.

2. A system as in claim 1, further comprising:

a second computer system for making a request for system resources from the first computer system;

a third computer system for generating a first digital certificate, the first digital certificate authorizing, at least in part, the second computer system to access a predefined system resource;

3. A system as in claim 2, further comprising:

a fourth computer system, the fourth computer system being operable to generate a second digital certificate, the second digital certificate authorizing, at least in part, the third computer system to authorize, at least in part, the user of the second computer system to access the predefined system resource.

4. A system as in claim 3, in which the third computer system is operable to send the first digital certificate to the second computer system, the second computer system is operable to send the first digital certificate to the first computer system in connection with said request, and the fourth computer system is operable to send the second digital certificate to the first computer system.

5. A system as in claim 4, in which the first computer system further comprises a public key associated with the fourth computer system, the public key corresponding to a private key used to sign the second digital certificate.

6. A system as in claim 1, in which at least some of the digital certificates comprise SPKI certificates.

7. A system as in claim 1, in which at least some of the digital certificates comprise Keynote certificates.

8. A method for performing trust management computations, the method including:

collecting a group of certificates, each certificate including at least one authorization;

expressing authorizations using a structure that satisfies certain predefined properties;

expressing each certificate as a function, wherein each function possesses one or more properties sufficient to ensure that a set of authorizations will have a fixpoint;

computing a fixpoint of the authorizations, or an approximation thereof;

making a trust management decision using the result of said computing step.

10. A method as in claim 8, in which the structure is chosen such that it provides an ordering for authorizations, a way to combine authorizations, and a way to express certificates as monotone functions.

9. A method as in 8, in which the structure comprises a lattice.

11. A method as in claim 9, in which the one or more properties sufficient to ensure that a set of authorizations will have a fixpoint includes the property that each function is monotone.

12. A system for controlling access to electronic content or processing resources, the system comprising:

means for receiving a request from a requesting principal to access a piece of electronic content or a processing resource;

means for collecting a set of one or more certificates relating to the request, the requesting principal, or the electronic content or processing resource;

means for identifying a root principal from whom authorization is needed in order to grant the request;

means for performing at least a portion of a least fixpoint computation over said certificates to determine whether the root principal has authorized access to the piece of electronic content or processing resource by the requesting principal; and

means for granting access to the electronic content or processing resource if the least fixpoint computation indicates that the root principal has authorized said access.