On error-correcting fingerprinting codes for use with watermarking

Schaathun, Hans Georg

doi:10.1007/s00530-007-0096-7

Cited by 17 publications

(18 citation statements)

References 20 publications

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“…In any practical implementation, they must be combined with an embedding scheme. The resulting system has two layers [6,12]: The coding layer determines which message to embed and protects against collusion attacks. The underlying watermarking layer hides symbols in segments of the content.…”

Section: Collusion Attacks Against Forensic Watermarkingmentioning

confidence: 99%

False positive probabilities in q-ary Tardos codes: comparison of attacks

Simone

Škorić

2014

Des. Codes Cryptogr.

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We investigate False Positive (FP) accusation probabilities for q-ary Tardos codes in the Restricted Digit Model. We employ a computation method recently introduced by us, to which we refer as Convolution and Series Expansion (CSE). We present a comparison of several collusion attacks on q-ary codes: majority voting, minority voting, Interleaving,μ-minimizing and Random Symbol (the q-ary equivalent of the Coin Flip strategy). The comparison is made by looking at the FP rate at approximately fixed False Negative rate. In nearly all cases we find that the strongest attack is either minority voting orμ-minimizing, depending on the exact setting of parameters such as alphabet size, code length, and coalition size.Furthermore, we present results on the convergence speed of the CSE method, and we show how FP rate computations for the Random Symbol strategy can be sped up by a precomputation step.

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Section: Collusion Attacks Against Forensic Watermarkingmentioning

confidence: 99%

False positive probabilities in q-ary Tardos codes: comparison of attacks

Simone

Škorić

2014

Des. Codes Cryptogr.

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“…In any practical implementation, they must be combined with some kind of embedding scheme. The resulting system has two layers [9,19]: The coding layer determines which message to embed and protects against collusion attacks. The underlying watermarking layer hides symbols of the message in segments of the content.…”

Section: Collusion Attacks Against Forensic Watermarkingmentioning

confidence: 99%

“…Such a full analysis is important for the following reason. As (19) shows, it is advantageous for the attackers not only to decreaseμ, but also to modify the shape of R m such that R inv m (ε 1 ) increases, i.e. such that the right-hand tail of the innocent's accusation probability becomes longer.…”

Section: The Gaussian Approximationmentioning

confidence: 99%

Accusation probabilities in Tardos codes: beyond the Gaussian approximation

Simone

Škorić

2011

Des. Codes Cryptogr.

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We study the probability distribution of user accusations in the q-ary Tardos fingerprinting system under the Marking Assumption, in the restricted digit model. In particular, we look at the applicability of the so-called Gaussian approximation, which states that accusation probabilities tend to the normal distribution when the fingerprinting code is long. We introduce a novel parametrization of the attack strategy which enables a significant speedup of numerical evaluations. We set up a method, based on power series expansions, to systematically compute the probability of accusing innocent users. The 'small parameter' in the power series is 1/m, where m is the code length. We use our method to semi-analytically study the performance of the Tardos code against majority voting and interleaving attacks. The bias function 'shape' parameter κ strongly influences the distance between the actual probabilities and the asymptotic Gaussian curve. The impact on the collusion-resilience of the code is shown. For some realistic parameter values, the false accusation probability is even lower than the Gaussian approximation predicts. Keywords

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“…Thus this attacker model is less strong than the one we use; codes for their model, based on the Boneh-Shaw code, can be found in [4,8].…”

Section: Related Workmentioning

confidence: 99%

“…As these are only codes, they must be combined with some kind of embedding scheme (or modulation), such as a watermarking system. This can be viewed as a two-layer model [5,8], where the coding layer encodes user identities to protect against collusion attacks, and the underlying watermarking layer hides the message in the digital contents.…”

Section: Introductionmentioning

confidence: 99%

Tardos fingerprinting codes in the combined digit model

Skoric¹,

Katzenbeisser²,

Schaathun³

et al. 2009

2009 First IEEE International Workshop on Information Forensics and Security (WIFS)

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We introduce a new attack model for collusion secure codes, and analyze the collusion resistance of two version of the Tardos code in this model, both for binary and non-binary alphabets. The model allows to consider signal processing and averaging attacks via a set of symbol detection error rates. The false positive rate is represented as a single number; the false negative rate is a function of the false positive rate and of the number of symbols mixed by the colluders.We study two versions of the q-ary Tardos code in which the accusation method has been modified so as to allow for the detection of multiple symbols in the same content segment. The collusion resilience of both variants turns out to be comparable. For realistic attacker strengths the increase in code length is modest, demonstrating that the modified Tardos code is effective in the new model.

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On error-correcting fingerprinting codes for use with watermarking

Cited by 17 publications

References 20 publications

False positive probabilities in q-ary Tardos codes: comparison of attacks

False positive probabilities in q-ary Tardos codes: comparison of attacks

Accusation probabilities in Tardos codes: beyond the Gaussian approximation

Tardos fingerprinting codes in the combined digit model

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