Saving and Retrieving Data Based on Public Key Encryption

• US 20070088949A1
• Filed: 11/08/2006
• Published: 04/19/2007
• Est. Priority Date: 04/17/2002
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: England, Paul, Peinado, Marcus
• Granted Patent: US 7,765,397 B2
• Time in Patent Office: Days
• US Class Current: 713/167
• CPC Class Codes: G06F 21/6218 to a system of files or objects, e.g. local or distributed file system or database

Abstract

In accordance with certain aspects, data is received from a calling program. Ciphertext that includes the data is generated, using public key encryption, in a manner that allows only one or more target programs to be able to obtain the data from the ciphertext. In accordance with another aspect, a bit string is received from a calling program. An identifier of the calling program is checked to determine whether the calling program is allowed to access data encrypted in ciphertext of the bit string. The data is decrypted using public key decryption and returned to the calling program only if the calling program is allowed to access the data.

Claims

1. One or more computer readable media having stored thereon a plurality of instructions to implement a GenBoundKey operation, wherein the plurality of instructions, when executed by one or more processors of a computing device, causes the one or more processors to:

generate a data structure for a new bound key that is to be bound to the one or more processors, wherein the new bound key includes data that allows a private key of a public/private key pair to be recovered from the data structure; and

cryptographically protect the data structure.

2. One or more computer readable media as recited in claim 1, wherein the instructions that cause the one or more processors to cryptographically protect the data structure comprise instructions that cause the one or more processors to encrypt the data structure using a public key of the public/private key pair.

3. One or more computer readable media having stored thereon a plurality of instructions to implement a BoundKeyMigrate operation, wherein the plurality of instructions, when executed by one or more processors of a computing device, causes the one or more processors to:

receive, as an input, a bound key, wherein the bound key is bound to a program;

verify that a usage condition associated with the key can be changed by the program; and

change the usage condition if the verification is successful.

4. One or more computer readable media as recited in claim 3, wherein the usage condition comprises an identifier of a program to which the key is bound.

5. One or more computer readable media as recited in claim 3, wherein the instructions that cause the one or more processors to verify that a usage condition associated with the key can be changed by the program comprise instructions that cause the one or more processors to verify that the bound key is marked as being migrateable.

6. One or more computer readable media as recited in claim 3, wherein the instructions that cause the one or more processors to verify that a usage condition associated with the key can be changed by the program comprise instructions that cause the one or more processors to verify that the program calling the BoundKeyMigrate operation is permitted to migrate the bound key.

7. One or more computer readable media as recited in claim 3, wherein the instructions that cause the one or more processors to verify that a usage condition associated with the key can be changed by the program comprise instructions that cause the one or more processors to verify that a logical formula evaluates true.

8. One or more computer readable media as recited in claim 3, wherein the instructions that cause the one or more processors to verify that a usage condition associated with the key can be changed by the program comprise instructions that cause the one or more processors to verify that execution of a particular program returns an indication of true.

9. One or more computer readable media as recited in claim 3, wherein the instructions that cause the one or more processors to verify that a usage condition associated with the key can be changed by the program comprise instructions that cause the one or more processors to verify that a time constraint is satisfied.

10. One or more computer readable media as recited in claim 3, wherein the usage condition is an element of a data structure that includes the bound key.

11. One or more computer readable media having stored thereon a plurality of instructions to implement a BoundKeyExport operation, wherein the plurality of instructions, when executed by a processor of a computing device, causes the processor to:

receive, as an input, a bound key, wherein the bound key is bound to a guard;

verify that the key can be re-bound to a different guard; and

re-bind the key to the different guard if the verification is successful.

12. One or more computer readable media as recited in claim 11, wherein the guard comprises the processor and the different guard comprises another processor.

13. One or more computer readable media as recited in claim 11, wherein the different guard is identified as an input to the BoundKeyExport operation.

14. One or more computer readable media as recited in claim 11, wherein the instructions that cause the processor to verify that the key can be re-bound to a different guard comprise instructions that cause the processor to verify that the bound key is marked as being exportable.

15. One or more computer readable media as recited in claim 11, wherein the instructions that cause the processor to verify that the key can be re-bound to a different guard comprise instructions that cause the processor to verify that the program calling the BoundKeyExport operation is permitted to export the bound key.

16. One or more computer readable media as recited in claim 11, wherein the instructions that cause the processor to verify that the key can be re-bound to a different guard comprise instructions that cause the processor to verify that a logical formula evaluates true.

17. One or more computer readable media as recited in claim 11, wherein the instructions that cause the processor to verify that the key can be re-bound to a different guard comprise instructions that cause the processor to verify that execution of a particular program returns an indication of true.

18. One or more computer readable media as recited in claim 11, wherein the instructions that cause the processor to verify that the key can be re-bound to a different guard comprise instructions that cause the processor to verify that a time constraint is satisfied.