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This paper proposes a theory of watermarking security based on a cryptanalysis point of view. The main idea is that information about the secret key leaks from the observations, for instance, watermarked pieces of content, available to the opponent. Tools from information theory (Shannon's mutual information and Fisher's information matrix) can measure this(More)
We consider the problem of hiding information in a steganographic framework, i.e. embedding a binary message within an apparently innocuous content, in order to establish a 'suspicion-free' digital communication channel. The adversary is passive as no intentional attack is foreseen. The only threat is that she discovers the presence of a hidden(More)
This paper considers watermarking detection, also known as zero-bit watermarking. A watermark, carrying no hidden message, is inserted in content. The watermark detector checks for the presence of this particular weak signal in content. The paper aims at looking to this problem from a classical detection theory point of view, but with side information(More)
This paper discusses a novel strategy for simulating rare events and an associated Monte Carlo estimation of tail probabilities. Our method uses a system of interacting particles and exploits a Feynman-Kac representation of that system to analyze their fluctuations. Our precise analysis of the variance of a standard multilevel splitting algorithm reveals an(More)
This paper presents our recent works on multimedia fingerprinting, improving both the fingerprinting code and the watermarking scheme. Our first contribution focuses on deriving a better accusation process for the well known Tardos codes. It appears that Tardos orginal decoding is very conservative: its performances are guaranteed whatever the collusion(More)
Content-Based Image Retrieval Systems used in forensics related contexts require very good image recognition capabilities. Therefore they often use the SIFT local-feature description scheme as its robustness against a large spectrum of image distortions has been assessed. In contrast, the <i>security</i> of SIFT is still largely unexplored. We show in this(More)
The class of joint decoder in fingerprinting codes is of utmost importance in theoretical papers to establish the concept of fingerprint capacity. However, no implementation supporting a large user base is known to date. This paper presents an iterative decoder which is the first attempt toward practical large-scale joint decoding. The discriminative(More)
This article presents an asymmetric watermarking method as an alternative to classical Direct Sequence Spread Spectrum and Watermarking Costa Schemes techniques. This new method provides a higher security level against malicious attacks threatening watermarking techniques used for a copy protection purpose. This application, which is quite different from(More)
We consider a particular design of fingerprinting code for multimedia contents, carefully motivated by a detailed analysis. This design is based on a two-layer approach: a probabilistic fingerprinting code a la Tardos coupled with a zero-bit side informed watermarking technique. The detection of multiple watermark presences in content blocks give birth to(More)