Protecting documents with centralized and discretionary policies
A technique and system protects documents at rest and in motion using declarative policies, access rights, and encryption. Methods, techniques, and systems control access to documents and use of content in documents to support information management policies.
1. A method comprising:
providing a data protection client on a computing device having a first plurality of policies;
providing a user attempting to open a document using an application program on the computing device;
detecting a file open operation in the application program by the data protection client;
sending the file open operation by the data protection client to a policy engine to determine if the file open operation is allowed;
selecting a first subset of policies from the first plurality of policies relevant to the file open operation, the document and the user by the policy engine;
evaluating the first subset of policies to produce a first policy decision;
in response to the first policy decision to allow the file open operation, determining if the document includes a second plurality of policies;
if the document includes the second plurality of policies, retrieving the second plurality of policies from the document;
if the document includes the second plurality of policies, selecting a second subset of policies from the second plurality of policies relevant to the file operation and the user;
if the document includes the second plurality of policies, evaluating the second subset of policies to produce a second policy decision;
if the document includes the second plurality of policies, combining the first policy decision and the second policy decision to produce a third policy decision;
if the document does not include the second plurality of policies, making the third policy decision equal to the first policy decision;
if the third policy decision allows the file open operation, allowing the file open operation to continue, wherein the document opens in the application program; and
if the third policy decision does not allow the file open operation, blocking the file open operation by the data protection client, wherein the document fails to open in the application program.
2. The method of claim 1 wherein the first plurality of policies is sent from a policy server.
3. The method of claim 1 wherein the first plurality of policies is access or use control policies.
4. The method of claim 1 wherein the first plurality of policies is rights control policies.
5. The method of claim 1 wherein the second plurality of policies is discretionary policies.
6. The method of claim 1 wherein the data protection client instruments the application program to detect application program operations.
7. The method of claim 1 wherein the detecting a file open operation in the application program by the data protection client is performed in a policy enforcement point of the data protection client.
8. The method of claim 1 wherein a policy in the first subset of policies is assigned an authority level.
9. The method of claim 1 wherein a policy in the first subset of policies does not have an authority level.
10. The method of claim 9 wherein the authority level is an integer.
11. The method of claim 9 wherein the authority level is a named value.
12. The method of claim 1 wherein an author of a policy in the second subset of policies is assigned an authority level.
13. The method of claim 12 wherein the policy in the second subset of policies inherits the authority level from an author.
14. The method of claim 1 wherein a policy in the second subset of policies does not have an authority level.
15. The method of claim 1 wherein the first policy decision is one of allow or deny.
16. The method of claim 1 wherein the combining the first policy decision and the second policy decision to produce the third policy decision comprises the third policy decision allows the file open operation if the first policy decision allows the file open operation.
17. The method of claim 1 wherein the combining the first policy decision and the second policy decision to produce the third policy decision comprises the third policy decision does not allow the file open operation if the first policy decision allows the file open operation and the second policy decision does not allow the file open operation.
18. The method of claim 1 wherein the first policy decision comprises a decision to allow or deny access to the document and the second plurality of policies comprises one or more policies that determine, after access is allowed, what operations may be performed on the document.
19. The method of claim 1 wherein evaluating the first subset of policies to produce a first policy decision further includes:
determining a first highest authority level in the first subset of policies; and
excluding, based on the first highest authority level, one or more policies from the evaluating.
20. The method of claim 19 wherein the first highest authority level is based at least in part on an author of a policy with the first highest authority level.