Cramér-Rao bound on watermark desynchronization parameter estimation accuracy

Shankar Sadasivam, Pierre Moulin

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Various decoding algorithms have been proposed in the literature to combat desynchronization attacks on quantization index modulation (QIM) blind watermarking schemes. Nevertheless, these results have been fairly poor so far. The need to investigate fundamental limitations on the decoder's performance under a desynchronization attack is thus clear. In this paper, we look at the class of estimator-decoders which estimate the desynchronization attack parameter(s) for using in the decoding step. We model the desynchronization attack as an arbitrary (but invertible) linear time-invariant (LTI) system. We then come up with an encoding-decoding scheme for these attacks on cubic QIM watermarking schemes, and derive Cramér-Rao bounds on the estimation error for the desynchronization parameter at the decoder. As an example, we consider the case of a cyclic shift attack and present some numerical findings.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE-IS and T Electronic Imaging - Security, Steganography, and Watermarking of Multimedia Contents IX
StatePublished - Sep 3 2007
EventSecurity, Steganography, and Watermarking of Multimedia Contents IX - San Jose, CA, United States
Duration: Jan 29 2007Feb 1 2007

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherSecurity, Steganography, and Watermarking of Multimedia Contents IX
Country/TerritoryUnited States
CitySan Jose, CA


  • Blind watermarking
  • Cramér-Rao lower bound
  • DC-QIM watermarking
  • Desynchronization attack
  • Fisher information
  • Joint estimator-decoder

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Cramér-Rao bound on watermark desynchronization parameter estimation accuracy'. Together they form a unique fingerprint.

Cite this