Tackling BOWS with the sensitivity attack

Abstract

We present our results in the first BOWS challenge (Break Our Watermarking System). There were three given digital photos containing an invisible watermark that was introduced using informed coding and embedding. The goal was to remove the watermark from the photos while keeping a minimum quality of at least 30 dB PSNR (peak signal to noise ratio).We focus on the method used to win the second phase of the contest with about 58 dB PSNR (18 dB ahead of the best fellow contributions). This method will be viewed from three different perspectives: Phase one and two of the contest as well as with complete knowledge about the implementation and the secret key.