Method, Apparatus, and Program Product for Flexible Redaction of Content

• US 20080046757A1
• Filed: 12/15/2006
• Published: 02/21/2008
• Est. Priority Date: 07/12/2006
• Status: Active Grant

• Current Assignee: Majandro LLC (IP Edge LLC)
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: Staddon, Jessica N., Golle, Philippe Jean-Paul
• Granted Patent: US 7,873,838 B2
• Time in Patent Office: Days
• US Class Current: 713/189
• CPC Class Codes: H04L 9/088 Usage controlling of secret information, e.g. techniques for restricting cryptographic keys to pre-authorized uses, different access levels, validity of crypto-period, different key- or password length, or different strong and weak cryptographic algorithms network architectures or network communication protocols for using time-dependent keys in a packet data network H04L63/068
• CPC Class Codes: H04L 9/0894 Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage

Abstract

A selectively encrypted data unit is generated from an unencrypted data unit. This is accomplished by accessing a list of attributes related to the unencrypted data unit that identify classifications of sensitive information within the unencrypted data unit. In addition, a protection key that is responsive to a random number is selected and auxiliary values computed from the attributes of the sensitive information and the random number are produced. The sensitive information is encrypted with the protection key to create an encrypted version of the sensitive information. The encrypted version is associated with the auxiliary values and linked to an attribute vector that classifies the sensitive information in the encrypted version. Data from the unencrypted data unit and the encrypted version of the sensitive information is stored as the selectively encrypted data unit.

Claims

1. A computer controlled method for generating a selectively encrypted data unit from an unencrypted data unit comprising:

accessing a list of attributes related to said unencrypted data unit;

accessing said unencrypted data unit, said unencrypted data unit comprising a sequence of data;

identifying sensitive information within said sequence of data associated with one or more of said list of attributes;

selecting a protection key, said protection key responsive to a random number;

computing a plurality of auxiliary values responsive to said one or more of said list of attributes and said random number;

encrypting said sensitive information with said protection key to create an encrypted version of said sensitive information, said encrypted version associated with said plurality of auxiliary values;

linking an attribute vector with said encrypted version, said attribute vector responsive to said one or more of said list of attributes associated with said encrypted version; and

storing, as said selectively encrypted data unit, data from said unencrypted data unit and said encrypted version of said sensitive information.

2. The computer controlled method of claim 1, wherein selecting further comprises selecting an access key responsive to a second random number.

3. The computer controlled method of claim 1, wherein said unencrypted data unit is one of a collection of data units, said list of attributes is related to said collection of data units, and said collection of data units comprises one or more electronic files.

4. The computer controlled method of claim 3, wherein said collection of data units is a document collection, said unencrypted data unit is an electronic document, said sequence of data is a cleartext string, said sensitive information is a subset of said cleartext string, said encrypted version is ciphertext, and said selectively encrypted data unit is a redacted electronic document.

5. The computer controlled method of claim 3, further comprising analyzing said collection of data units to determine said list of attributes.

6. The computer controlled method of claim 5, further comprising storing said list of attributes with said collection of data units.

7. The computer controlled method of claim 1, wherein said plurality of auxiliary values comprises one or more user-oriented values and wherein computing further comprises computing said one or more user-oriented values responsive to said random number, a set of revoked users and a polynomial.

8. The computer controlled method of claim 1, wherein said unencrypted data unit includes one or more of a group consisting of scanned document image data, audio data, video data, graphical data, personally identifiable data, image data, and textual data.

9. The computer controlled method of claim 1, wherein linking said attribute vector includes one or more of a group consisting of:

storing said attribute vector near said encrypted version, storing said attribute vector at a specified location within said unencrypted data unit, storing said attribute vector as metatext, storing said attribute vector in a second file unit, storing said attribute vector in a database and storing said attribute vector for access through a server computer.

10. The computer controlled method of claim 1, wherein said one or more attributes specify one or more of a group consisting of personally identifiable data, one or more restricted numbers, one or more restricted topics, one or more metadata values, one or more text characteristics, one or more identified ranges of restricted data, or one or more restricted images

11. The computer controlled method of claim 1, wherein said attribute vector indicates which of said list of attributes are associated with said sensitive information.

12. The computer controlled method of claim 11, wherein said attribute vector is a compressed Boolean array indicating which of said list of attributes are true with respect to said sensitive information.

13. The computer controlled method of claim 1, further comprising computing a protection map configured to locate said encrypted version within said selectively encrypted data unit.

14. An apparatus having a central processing unit (CPU) and a memory coupled to said CPU configured to generate a selectively encrypted data unit from an unencrypted data unit, the apparatus comprising:

an attribute access logic configured to access a list of attributes related to said unencrypted data unit;

a data access logic configured to access said unencrypted data unit, said unencrypted data unit comprising a sequence of data;

a data selection logic configured to identify sensitive information within said sequence of data associated with one or more of said list of attributes accessed by the data access logic and the attribute access logic;

a key selection logic configured to select a protection key, said protection key responsive to a random number;

a first value generation logic configured to compute a plurality of auxiliary values responsive to said one or more of said list of attributes accessed by the attribute access logic and said random number used by the key selection logic;

an encryption logic configured to encrypt said sensitive information identified by the data selection logic with said protection key selected by the key selection logic to create an encrypted version of said sensitive information, said encrypted version associated with said plurality of auxiliary values;

a vector association logic configured to link an attribute vector with said encrypted version responsive to the encryption logic, said attribute vector responsive to said one or more of said list of attributes associated with said encrypted version; and

a storage logic configured to store, as said selectively encrypted data unit, data from said unencrypted data unit and said encrypted version of said sensitive information.

15. The apparatus of claim 14, wherein the key selection logic is further configured to select an access key responsive to a second random number.

16. The apparatus of claim 14, wherein said unencrypted data unit is one of a collection of data units, said list of attributes is related to said collection of data units, and said collection of data units comprises one or more electronic files.

17. The apparatus of claim 16, wherein said collection of data units is a document collection, said unencrypted data unit is an electronic document, said sequence of data is a cleartext string, said sensitive information is a subset of said cleartext string, said encrypted version is ciphertext, and said selectively encrypted data unit is a redacted electronic document.

18. The apparatus of claim 16, further comprising a data analysis logic configured to analyze said collection of data units to determine said list of attributes.

19. The apparatus of claim 18, further comprising an attribute storage logic configured to store said list of attributes with said collection of data units.

20. The apparatus of claim 14, wherein said plurality of auxiliary values comprises one or more user-oriented values and wherein the first value generation logic further comprises a second value generation logic configured to compute said one or more user-oriented values responsive to said random number, a set of revoked users and a polynomial.

21. The apparatus of claim 14, wherein said unencrypted data unit includes one or more of a group consisting of scanned document image data, audio data, video data, graphical data, personally identifiable data, image data, and textual data.

22. The apparatus of claim 14, wherein the vector association logic includes one or more logics configured to perform one or more operations selected from a group consisting of:

storing said attribute vector near said encrypted version, storing said attribute vector at a specified location within said unencrypted data unit, storing said attribute vector as metatext, storing said attribute vector in a second file unit, storing said attribute vector in a database and storing said attribute vector for access through a server computer.

23. The apparatus of claim 14, wherein said one or more attributes specify one or more of a group consisting of personally identifiable data, one or more restricted numbers, one or more restricted topics, one or more metadata values, one or more text characteristics, one or more identified ranges of restricted data, or one or more restricted images

24. The apparatus of claim 14, wherein said attribute vector indicates which of said list of attributes are associated with said sensitive information.

25. The apparatus of claim 24, wherein said attribute vector is a compressed Boolean array indicating which of said list of attributes are true with respect to said sensitive information.

26. The apparatus of claim 14, further comprising a directory logic configured to compute a protection map configured to locate said encrypted version within said selectively encrypted data unit.

27. A computer program product comprising:

a computer-usable data carrier providing instructions that, when executed by a computer, cause said computer to perform a method to generate a selectively encrypted data unit from an unencrypted data unit, said method comprising;

accessing a list of attributes related to said unencrypted data unit;

accessing said unencrypted data unit, said unencrypted data unit comprising a sequence of data;

identifying sensitive information within said sequence of data associated with one or more of said list of attributes;

selecting a protection key, said protection key responsive to a random number;

computing a plurality of auxiliary values responsive to said one or more of said list of attributes and said random number;

encrypting said sensitive information with said protection key to create an encrypted version of said sensitive information, said encrypted version associated with said plurality of auxiliary values;

linking an attribute vector with said encrypted version, said attribute vector responsive to said one or more of said list of attributes associated with said encrypted version; and

storing, as said selectively encrypted data unit, data from said unencrypted data unit and said encrypted version of said sensitive information.

28. The computer program product of claim 27, selecting further comprises selecting an access key responsive to a second random number.

29. The computer program product of claim 27, wherein said unencrypted data unit is one of a collection of data units, said list of attributes is related to said collection of data units, and said collection of data units comprising one or more electronic files.

30. The computer program product of claim 27, wherein said plurality of auxiliary values comprises one or more user-oriented values and wherein computing further comprises computing said one or more user-oriented values responsive to said random number, a set of revoked users and a polynomial.

31. The computer program product of claim 27, wherein said unencrypted data unit includes one or more of a group consisting of scanned document image data, audio data, video data, graphical data, personally identifiable data, image data, and textual data.

32. The computer program product of claim 27, wherein linking said attribute vector includes one or more of a group consisting of:

storing said attribute vector near said encrypted version, storing said attribute vector at a specified location within said unencrypted data unit, storing said attribute vector as metatext, storing said attribute vector in a second file unit, storing said attribute vector in a database and storing said attribute vector for access through a server computer.

33. The computer program product of claim 27, wherein said one or more attributes specify one or more of a group consisting of personally identifiable data, one or more restricted numbers, one or more restricted topics, one or more metadata values, one or more text characteristics, one or more identified ranges of restricted data, or one or more restricted images.