Nearest neighbor decoding for Tardos fingerprinting codes

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

2 Citations (Scopus)


Over the past decade, various improvements have been made to Tardos' collusion-resistant fingerprinting scheme [Tardos, STOC 2003], ultimately resulting in a good understanding of what is the minimum code length required to achieve collusion-resistance. In contrast, decreasing the cost of the actual decoding algorithm for identifying the potential colluders has received less attention, even though previous results have shown that using joint decoding strategies, deemed too expensive for decoding, may lead to better code lengths. Moreover, in dynamic settings a fast decoder may be required to provide answers in real-time, further raising the question whether the decoding costs of score-based fingerprinting schemes can be decreased with a smarter decoding algorithm. In this paper we show how to model the decoding step of scorebased fingerprinting as a nearest neighbor search problem, and how this relation allows us to apply techniques from the field of (approximate) nearest neighbor searching to obtain decoding times which are sublinear in the total number of users. As this does not affect the encoding and embedding steps, this decoding mechanism can easily be deployed within existing fingerprinting schemes, and this may bring a truly efficient joint decoder closer to reality. Besides the application to fingerprinting, similar techniques can potentially be used to decrease the decoding costs of group testing methods, which may be of independent interest.

Original languageEnglish
Title of host publicationIH and MMSec 2019 - Proceedings of the ACM Workshop on Information Hiding and Multimedia Security
Place of PublicationNew York
PublisherAssociation for Computing Machinery, Inc
Number of pages6
ISBN (Electronic)978-1-4503-6821-6
Publication statusPublished - 2 Jul 2019
Event7th ACM Workshop on Information Hiding and Multimedia Security, IH and MMSec 2019 - Paris, France
Duration: 3 Jul 20195 Jul 2019


Conference7th ACM Workshop on Information Hiding and Multimedia Security, IH and MMSec 2019


  • Collusion-resistance
  • Fingerprinting codes
  • Group testing
  • Nearest neighbor searching
  • Watermarking


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