SAVING AND RETRIEVING DATA BASED ON PUBLIC KEY ENCRYPTION

• US 20110119500A1
• Filed: 01/27/2011
• Published: 05/19/2011
• 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 8,683,230 B2
• Time in Patent Office: Days
• US Class Current: 713/189
• 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 the data to be obtained from the ciphertext only if one or more conditions are satisfied. In accordance with another aspect, a bit string is received from a calling program. Data in the bit string is decrypted using public key decryption and returned to the calling program only if one or more conditions included in the bit string are satisfied.

Claims

1. A method comprising:

obtaining data to be sealed and one or more conditions that are to be satisfied in order for the data to be unsealed; and

encrypting, using public key encryption, both the data and the one or more conditions to generate a ciphertext that includes both the encrypted data and the encrypted one or more conditions, wherein the data is not unsealed if the one or more conditions are not satisfied, wherein one of the one or more conditions comprises a logical formula to be evaluated, and wherein the data can be unsealed only if the logical formula evaluates true.

2. A method as recited in claim 1, wherein the data comprises a cryptographic key.

3. A method as recited in claim 1, wherein obtaining the data comprises receiving the data as part of a PKSeal operation.

4. A method as recited in claim 1, wherein the logical formula comprises a statement written in first order logic.

5. A method comprising:

invoking an operation to seal data; and

receiving, in response to invoking the operation, a ciphertext including both the data and one or more conditions that are to be satisfied in order for the data to be unsealed, wherein one of the one or more conditions comprises a logical formula to be evaluated and wherein the data can be unsealed only if the logical formula evaluates true, wherein the data is not unsealed if the one or more conditions are not satisfied, and wherein the data and the one or more conditions are encrypted using public key encryption.

6. A method as recited in claim 5, wherein the operation comprises a PKSeal operation.

7. A method as recited in claim 5, wherein invoking the operation comprises passing the data as an input to the operation.

8. A method as recited in claim 5, wherein invoking the operation comprises passing at least one of the one or more conditions as an input to the operation.

9. A method as recited in claim 5, wherein the data comprises a cryptographic key.

10. A method as recited in claim 5, wherein the logical formula comprises a statement written in first order logic.

11. A method comprising:

invoking an operation to have ciphertext decrypted; and

receiving, in response to invoking the operation, decrypted data from the ciphertext only if one or more conditions included in the ciphertext are satisfied, wherein the one or more conditions comprises a logical formula to be evaluated true, and wherein the ciphertext is decrypted using public key decryption.

12. A method as recited in claim 11, wherein the operation comprises a PKUnseal operation.

13. A method as recited in claim 11, wherein invoking the operation comprises passing the ciphertext as an input to the operation.

14. A method as recited in claim 11, wherein invoking the operation comprises passing a pointer to the ciphertext as an input to the operation.

15. A method as recited in claim 11, wherein the data comprises a cryptographic key.

16. A method as recited in claim 11, wherein the logical formula comprises a statement written in first order logic.