Security of Invertible Media Authentication Schemes Revisited

Abstract. Dittmann, Katzenbeisser, Schallhart and Veith (IACR ePrint 2004) introduced the notion of invertible media authentication schemes, embedding authentication data in media objects via invertible watermarks. These invertible watermarks allow to recover the original media object (given a secret encryption key), as required for example in some medical applications where the distortion must be removable. Here we revisit the approach of Dittmann et al. from a cryptographic viewpoint, clarifying some important aspects of their security definitions. Namely, we first discuss that their notion of unforgeability may not suffice in all settings, and we therefore propose a strictly stronger notion. We then show that the basic scheme suggested by Dittmann et al. achieves our notion if instantiated with the right cryptographic primitives. Our proof also repairs a flaw in the original scheme, pointed out by Hopper, Molnar and Wagner (TCC 2007). We finally address the issue of secrecy of m...

• Type: Conference
• Year: 2007
• Where: IH
• Authors: Daniel Dönigus, Stefan Endler, Marc Fischlin, Andreas Hülsing, Patrick Jäger, Anja Lehmann, Sergey Podrazhansky, Sebastian Schipp, Erik Tews, Sven Vowe, Matthias Walthart, Frederik Weidemann
• Keywords: Dittmann Et Al, IH 2007, Media Authentication Schemes, Media Object