DATA OBFUSCATION SYSTEM, METHOD, AND COMPUTER IMPLEMENTATION OF DATA OBFUSCATION FOR SECRET DATABASES

• US 20110179011A1
• Filed: 05/12/2009
• Published: 07/21/2011
• Est. Priority Date: 05/12/2008
• Status: Active Grant

• Current Assignee: New BIS Safe Luxco S.A R.L
• Original Assignee: Business Intelligence Solutions Safe B.V.
• Inventors: Cardno, Andrew John, Singh, Ashok Kumar
• Granted Patent: US 9,305,180 B2
• Time in Patent Office: Days
• US Class Current: 707/709
• CPC Class Codes: G06F 16/90 Details of database functions independent of the retrieved data types
• CPC Class Codes: G06F 21/6227 where protection concerns the structure of data, e.g. records, types, queries
• CPC Class Codes: G06F 21/6254 by anonymising data, e.g. decorrelating personal data from the owner's identification
• CPC Class Codes: G06F 30/00 Computer-aided design [CAD]
• CPC Class Codes: H04L 9/0662 with particular pseudorandom sequence generator
• CPC Class Codes: H04L 9/0822 using key encryption key

Abstract

A data obfuscation system, method, and computer implementation via software or hardware allows a legitimate user to gain access via a query to data of sufficient granularity to be useful while maintaining the confidentiality of sensitive information about individual records. Output values of a data request are obfuscated in a repeatable manner, via the use of an Obfuscating Function (OF), while maintaining the amount of obfuscation within a range so that the transformed values provide to a user information of a prescribed level of granularity. The data obfuscating system and method is particularly applicable to databases. The data obfuscation engine may be implemented in hardware and/or software within a stand alone or distributed environment.

Claims

1. A method of obfuscating data so that output values of a data request are obfuscated in a repeatable manner, via the use of an Obfuscating Function (OF) whilst maintaining the amount of obfuscation within a range so that the transformed values provide to a user information of a prescribed level of granularity.

2. A method of obfuscating data as claimed in claim 1 wherein the OF uses a transformation used in mathematical modeling.

3. A method of obfuscating data as claimed in claim 2, wherein the transformation is based upon the method of weighted regression.

7. A method of obfuscating data as claimed in claim 3 based upon minimizing a Total Weighted Error.

8. A method of obfuscating data as claimed in claim 7 in which the Total Weighted Error is defined to be the Sum of Squared Errors.

15. A method of obfuscating data as claimed in claim 3 including perturbing values to obtain a dependent variable for the weighted regression.

16. A method of obfuscating data as claimed in claim 3, in which the true data value can be used as the independent variable.

17. A method of obfuscating data as claimed in claim 15, based upon addition of random errors to true values to form a dependent variable y for weighted regression, and using the true data value as the independent variable.

18. A method of obfuscating data as claimed in claim 3, which is based upon using the true data value as the dependent variable, some function of the true data value as the independent variable, and fitting a regression equation.

19. A method of obfuscating data as claimed in claim 3, which is based upon using the true data value as the dependent variable, some function of the true data value and values in other columns as the set of independent variables, and fitting a regression equation.

20. A method of obfuscating data as claimed in claim 16 including selecting a subset of records on which the method of weighted regression will be applied to obtain an obfuscating function.

25. A method of obfuscating data as claimed in claim 2, which is based upon the Taylor Series Expansion of a function of values in the database.

26. A method of obfuscating data of claim 1, in which frequency data having a first level of granularity is shown to the user at a second level of granularity, coarser than the first level of granularity, wherein the data is converted from the first level of granularity to the second level of granularity according to a rule other than the simple proximity of the data to the nearest value at the second level of granularity.

27. A method of obfuscating data, as claimed in claim 26, that is a mapping based method based on the last digit.

28. A method of obfuscating data, as claimed in claim 26, using random rounding based upon an odd number being rounded up and an even number being rounded down.

29. A method of obfuscating data, as claimed in claim 26, using random rounding based upon an even number being rounded up and an odd number being rounded down,

30. A method of obfuscating data, as claimed in claim 26, using a pseudo random number seeding function which will seed a random number generator with input values, with its output either rounded up or rounded down, or results shifted by a rounded amount up or down

31. A method of obfuscating data, as claimed in claim 26, using a pseudo random number seeding function which will seed a random number generator with input values, with its output either shifted up or down a number of granularity factors.

37. A method of obfuscating data as claimed in claim 1 including a high frequency filter configured to hamper attempts to determine the true values from the obfuscated values.

41. A method of obfuscating data as claimed in claim 1 in which the obfuscated values are anticipated and pre-calculated.

42. A method of obfuscating data as claimed in claim 1 wherein the data request consists of multiple logical components, each being applied separately.

45. A method of obfuscating data as claimed in claim 42 in which restrictions are applied to the data relating to the granularity of the frequency data.

46. A method of obfuscating data as claimed in claim 1 in which the amount of obfuscation is altered in response to an algorithm.

47. A method as claimed in claim 46 where the alteration of the amount of obfuscation is made in response to different use access rights.

48. A method as claimed in claim 47 where the alteration of the amount of obfuscation is made in response to different levels of frequency of output aggregation allowing the data to be of sufficient quality to make business decisions.

68. A method as claimed in claim 1 wherein the frequency of each output value is determined at a first level of granularity and converted to a second level of granularity, coarser than the first level of granularity, wherein the data is converted from the first level of granularity to the second level of granularity according to a rule other than the simple proximity of the data to the nearest value at the second level of granularity.

4-6. -6. (canceled)

9-14. -14. (canceled)

21-24. -24. (canceled)

32-36. -36. (canceled)

38-40. -40. (canceled)

43-44. -44. (canceled)

49-67. -67. (canceled)

69. A method of representing data having a first level of granularity at a second level of granularity, coarser than the first level of granularity, wherein the data is converted from the first level of granularity to the second level of granularity according to a rule other than the simple proximity of the data to the nearest value at the second level of granularity.

73. A method of obfuscating data, as claimed in claim 69, using a pseudo random number seeding function which will seed a random number generator with input values, with its output either rounded up or rounded down, or results shifted by a rounded amount up or down

74. A method of obfuscating data, as claimed in claim 69, using a pseudo random number seeding function which will seed a random number generator with input values, with its output either shifted up or down a number of granularity factors.

70-72. -72. (canceled)

75-82. -82. (canceled)

83. A method of obfuscating data comprising:

running an unconstrained query on data in a secret database to produce output data; and

obfuscating the output data using a repeatable obfuscation function to return obfuscated data in response to the query.

84-94. -94. (canceled)