METHOD FOR OBFUSCATING THE DISPLAY OF TEXT

• US 20160092409A1
• Filed: 09/26/2014
• Published: 03/31/2016
• Est. Priority Date: 09/26/2014
• Status: Active Grant

• Current Assignee: Guy Le Henaff
• Original Assignee: Guy Le Henaff
• Inventors: LE HENAFF, Guy
• Granted Patent: US 10,402,471 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 40/106 Display of layout of documents; Previewing
• CPC Class Codes: G06F 40/109 Font handling; Temporal or kinetic typography
• CPC Class Codes: G06T 11/203 Drawing of straight lines or curves
• CPC Class Codes: H04L 2209/16 Obfuscation or hiding, e.g. involving white box
• CPC Class Codes: H04L 67/60 Scheduling or organising the servicing of application requests, e.g. requests for application data transmissions using the analysis and optimisation of the required network resources admission control or resource allocation H04L47/70

Abstract

The present document describes system and method for securing a text against copying and tampering. The system introduces a reversible change within the instructions contained in the electronic page description language defining the text. In a non-limiting example, the reversible change may include replacing the font used in the PDL by a customized font defining a set of changes from the standard/existing fonts. The system may then generate a set of instructions reversing the set of changes to display the proper text to the user. However, should any tampering or illegal copying of the text occur, the original text will not be displayed because a portion of the reversible change is not present. The reversible changes introduced may affect character sizes, colors, spacing, positions, mapping etc.

Claims

1. A method for obfuscating an electronic document including a text, the method comprising:

detecting an existing font used in an electronic page description of the electronic document;

replacing the existing font with a customized font, said customized font including a first set of changes that distinguish the customized font from the existing font;

modifying instructions of the electronic page description including introducing a second set of changes, the second set of changes being configured to reverse the first set of changes;

thereby producing an obfuscated electronic document which allows for displaying the text only when the first set of changes and the second set of changes are present at rendering time.

2. The method of claim 1, wherein replacing the existing font comprises analyzing the existing font and modifying the existing font using a set of controlled randomization changes to generate the customized font from the existing font.

3. The method of claim 1, further comprising providing one of:

the customized font and the second set of changes at rendering time.

4. The method of claim 3, further comprising providing, in the electronic page description, instructions which when executed allow for retrieving the customized font or the second set of changes from a local or remote memory.

5. The method of claim 1, wherein the existing font is a standard font, a base font fetched from a library of fonts, or a non-standard font that complies with the PDL.

6. The method of claim 1, wherein introducing a second set of changes comprises introducing changes affecting character to glyph mapping wherein the second set of changes include instructions to display a different text.

7. The method of claim 1, wherein introducing a second set of changes comprises introducing changes affecting sizes of characters.

8. The method of claim 1, wherein introducing a second set of changes comprises introducing changes affecting curves and/or control points defining the curves and/or lines.

9. The method of claim 1, wherein introducing a second set of changes comprises introducing changes affecting positions of characters and/or spacing between characters.

10. The method of claim 1, wherein introducing a second set of changes comprises introducing changes affecting character colors.

11. The method of claim 1, wherein introducing a second set of changes comprises introducing changes affecting one or more of:

sizes of characters, lines and/or curves and/or control points defining the curves, character to glyph mapping, and character colors.

12. A method for obfuscating an electronic document including a text, the method comprising:

searching for a font used in an electronic page description of the electronic document associated with the text;

if a font is detected introducing a reversible change in the electronic page description of the text, comprising replacing the detected font with a customized font including a set of changes and generating instructions to reverse an effect of the set of changes;

If no font is detected fetching a base font from a library and introducing a reversible change in the electronic page description of the text, comprising modifying the base font to include the set of changes and generating instructions to reverse the effect of the set of changes;

thereby producing a secure electronic document which allows for displaying the text only when the set of changes and the instructions reversing the set of changes are present at rendering time.

13. The method of claim 12, wherein replacing the detected font comprises analyzing the detected font and modifying the detected font using a set of controlled randomization changes to generate the customized font from the detected font.

14. The method of claim 12, further comprising providing one of:

the customized font and the second set of changes at rendering time.

15. The method of claim 14, further comprising providing, in the electronic page description, instructions which when executed allow for retrieving the customized font or the second set of changes from a local or remote memory.

16. An apparatus for obfuscating an electronic document including a text, the apparatus comprising:

a font detector adapted to detect an existing font used in an electronic page description (PDL) associated with the electronic document;

a font obfuscation module adapted to analyze the existing font and modify the existing font using a set of controlled randomization changes to generate a customized font having a first set of changes which differentiate the customized font from the existing font;

a PDL obfuscation module adapted to analyse the PDL and the first set of changes to modify the PDL by introducing a second set of changes configured to reverse an effect of the first set of changes; and

a PDL re-integration module adapted to integrate the second set of changes and the first set of changes into an obfuscated PDL which is compatible with conventional PDL readers.

17. The apparatus of claim 16, wherein the apparatus is configured to analyze the existing font and modify the existing font using a set of controlled randomization changes to produce the obfuscated font.

18. The apparatus of claim 16, wherein the font detector is configured to search for the existing font in the PDL and if no font is specified, the font detector is configured to fetch a base font from a library and set the base font as the existing font.

19. The apparatus of claim 16, wherein the apparatus is adapted to store the customized font or the second set of changes in a location outside the PDL and provide in the PDL instructions which when executed cause the customized font or the second set of changes to be retrieved at rendering time.

20. The apparatus of claim 19, wherein if one of the customized font and the second set of changes are absent at rendering time, execution of the PDL results in a different text being displayed.