1. 1 Formatted Text Document Data Hiding Robust to Printing,Copying and Scanning Speaker:Fanjia Yen Adviser:Quincy Wu Date:2008/04/10

2. 2 Outline Steganography ISM (Inter-word space) Modulation of the Inter-word Space Embedding rule Hidden Data Extraction Reference

3. 3 Steganography What to hide  Text  Images  Sound How to hide  Embed text in text/image/sound files  Embed image in text/image/sound files  Embed sound in text/image/sound files

4. 4 ISM (Inter-word space)(1/2) A space between adjacent words in a text row. There are nine inter-word spaces in the row. The actual length of the inter-word spaces in terms of number of pixels.  1 pixel -> 1 bit.  For example,”1”for black and “0” for white.

5. 5 ISM (Inter-word space)(2/2)

6. 6 Modulation of the Inter-word Space(1/2)

7. 7 Modulation of the Inter-word Space(2/2) After data embedding:

8. 8 Embedding rule(1/2)

9. 9 Embedding rule(2/2)

10. 10 Hidden Data Extraction(1/2)

11. 11 Hidden Data Extraction(2/2) If Φ A - Φ B >0, bit ‘1’ is extracted. If Φ A - Φ B <0, bit ‘0’ is extracted.

12. 12 Reference http://en.wikipedia.org/wiki/Steganography  wikipedia http://ms11.voip.edu.tw/~eddie/file/Formatted_Text_Document_Data _Hiding_Robust_to_Printing_Copying_and_Scanning.pdf http://ms11.voip.edu.tw/~eddie/file/Formatted_Text_Document_Data _Hiding_Robust_to_Printing_Copying_and_Scanning.pdf