Exploitation of redundancy for pattern estimation of copy-sensitive two level QR code

International audienceThe falsification of hardcopy documents is a common problem these days. Numerous industrial and scientific solutions have been proposed to prevent these falsifications. In this paper, we want to study the security of the two level QR code which is constructed using specific textured patterns that are sensitive to print-and-scan impact. Such code is a good candidate because it generalizes several concepts from several codes. We take a falsifier point of view that aims to reconstruct the two level QR code and to fool the au-thentication system detector. As the two level QR code contains sets of the same textured patterns, the opponent has access to different printed-and-scanned versions of these textured patterns. These sets of patterns can be used for structure estimation. Several local strategies for pattern estimation are suggest in this paper. The experimental results show that the increasing number of printed-and-scanned patterns cannot improve the estimation results