Method for obfuscating the display of text

• US 10,402,471 B2
• Filed: 09/26/2014
• Issued: 09/03/2019
• Est. Priority Date: 09/26/2014
• Status: Active Grant

• Current Assignee: Guy Le Henaff
• Original Assignee: Guy Le Henaff
• Inventors: Le Henaff, Guy
• Primary Examiner(s): Baderman, Scott T
• Assistant Examiner(s): Jung, Seung Woon
• Application Number:
  US14/498,247
• Publication Number:
  US 20160092409A1
• Time in Patent Office: 1,803 Days
• 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 an original text and an existing font for detecting tampering with the electronic document, the method comprising:

detecting in a page description language of the electronic document the existing font used for displaying the original text;

replacing the existing font with an obfuscated font, said obfuscated font including a first set of changes that distinguish the obfuscated font from the existing font, the first set of changes when executed cause a display of odd and/or abnormal and/or irregular and/or illegible shapes;

modifying the page description language including introducing instructions that implement a second set of changes within the page description language of the electronic document, the second set of changes reversing the first set of changes;

generating an obfuscated electronic document having an obfuscated page description language including the obfuscated font and a modified text and including the first set of changes and the second set of changes integrated with the obfuscated page description language for displaying the modified text as the original text wherein attempts to tamper with the obfuscated page description language will result in the display of the odd and/or abnormal and/or irregular and/or illegible shapes.

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 obfuscated font from the existing font.

3. 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 page description language.

4. The method of claim 1, wherein the first set of changes affect sizes of characters.

5. The method of claim 1, wherein the first set of changes affect curves and/or control points defining the curves and/or lines.

6. The method of claim 1, wherein the first set of changes affect drawing positions of characters and/or spacing between characters.

7. The method of claim 1, wherein the first set of changes affect character colors.

8. A computer having a processor and a memory accessed by the processor, the computer implementing the method of claim 1.

9. A method for obfuscating an electronic document including an original text for detecting tampering with the electronic document, the method comprising:

searching in a page description language of the electronic document for a font used for displaying the original text;

if the font is detected, introducing a reversible change in the electronic document, comprising replacing the detected font with an obfuscated font including a set of changes which when executed cause a display of odd and/or abnormal and/or irregular and/or illegible shapes within the original text and generating instructions to reverse an effect of the set of changes within the page description language of the electronic document;

if no font is detected, fetching a base font from a library and introducing the reversible change, comprising modifying the base font to include the set of changes to generate the obfuscated font, the set of changes when executed cause the display of the odd and/or abnormal and/or irregular and/or illegible shapes within the original text and generating instructions to reverse the effect of the set of changes within the page description language of the electronic document;

generating a secure electronic document having the obfuscated font including the set of changes and an obfuscated page description language including a modified text and the instructions reversing the set of changes for displaying the modified text as the original text whereby attempts to modify the original text and/or the font results in the display of the odd and/or abnormal and/or irregular and/or illegible shapes.

10. The method of claim 9, 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 obfuscated font from the detected font.

11. The method of claim 9, wherein the changes affect curves and/or control points defining the curves and/or lines and/or positions of characters and/or spacing between characters.

12. An apparatus comprising:

a processor and a memory device in communication with the processor and having recorded thereon computer readable statements and instructions for obfuscating an electronic document including an original text for detecting tampering with the electronic document, the apparatus further including;

a font detector module that detects an existing font used in an unobfuscated page description language (PDL) of the electronic document;

a font obfuscator module that analyzes the existing font and modifies the existing font using a set of controlled randomization changes to generate an obfuscated font having a first set of changes which differentiate the obfuscated font from the existing font and which when executed cause a display of odd and/or abnormal and/or irregular and/or illegible shapes;

a PDL obfuscator module that analyzes the unobfuscated PDL and the first set of changes to produce a second set of changes configured to reverse an effect of the first set of changes; and

a PDL re-integrator module that integrates the second set of changes and the first set of changes into an obfuscated PDL which is compatible with conventional PDL readers, and generates an obfuscated electronic document comprising the obfuscated PDL, the obfuscated font and a modified text that displays as the original text, whereby attempts to modify the text and/or the font result in the display of the odd and/or abnormal and/or irregular and/or illegible shapes;

wherein the font detector module and the PDL obfuscator module are each arranged to receive as an input the unobfuscated PDL, the font obfuscator module is arranged to receive the detected existing font from the font detector module, the PDL obfuscator module is in communication with the font obfuscator module, the PDL re-integrator module is connected to both the PDL obfuscator module and the font obfuscator module, and the PDL re-integrator module is arranged to output the obfuscated PDL.

13. The apparatus of claim 12, wherein the apparatus includes a set of controlled randomization changes that analyze the existing font and modify the existing font to produce the obfuscated font.

14. The apparatus of claim 12, wherein if no font is specified in the unobfuscated PDL, the font detector fetches a base font from a library and sets the base font as the existing font.

15. The apparatus of claim 12, wherein the changes affect curves and/or control points defining the curves and/or lines.

16. The apparatus of claim 15, wherein the changes affect one or more of:

positions of characters and/or spacing between characters; and

sizes of characters.