Traitor Tracing Jan-Jaap Oosterwijk Eindhoven University of Technology (TU/e) Department of Mathematics

©2012 Irdeto, All Rights Reserved. About myself  BSc & MSc in Mathematical Sciences at Utrecht University, NL  Internship (July – December 2012) at Irdeto Research Eindhoven, NL  PhD ( ) in Collusion-Resistant Traitor Tracing at Eindhoven University of Technology, NL 2

©2012 Irdeto, All Rights Reserved. Copyright Protection Don’t try to prevent, but trace, accuse and deter.  Prevention is impossible.  Trace who distributed an illegal copy.  Accuse such traitors to deter others. How? Mark and hide  Insert a unique code in each official copy of the digital document.  Place it in the same locations for all users, for easy retrieval  Make it imperceptible (watermark) to prevent the user from changing or removing it. 3

©2012 Irdeto, All Rights Reserved. Colluding traitors What’s imperceptible to one, might be visible for many.  Users can compare their copies bit by bit.  Where a bit differs, part of the watermark is located.  To prevent the traitors to locate the entire watermark, it should be made such that for each (small) group of users bits should often coincide. Codelength Add a little, gain a lot  The larger the coalition of traitors, the longer the code needs to be to trace them.  Content should be protected by adding as small a fingerprint as possible 4

©2012 Irdeto, All Rights Reserved. Accusation errors Two types:  Falsely accuse an innocent user  Not accuse any guilty user Allow some mistakes, but aim for perfection  Accusing an innocent user should be an extremely rare event  Sometimes not accusing any guilty user isn’t so bad: repeated offenders will be caught in the long run  Allows for much shorter codelength 5

©2012 Irdeto, All Rights Reserved. Research focus 6 Dynamic Static Watermark insertion Traitor attack Generic Specific known

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