From December 15, 2005 to June 15, 2006, the watermarking community was challenged to remove the watermark from 3 different 512 × 512 watermarked images while maximizing the peak signal-to-noise ratio (PSNR) measured by comparing the watermarked signals with their attacked counterparts. This challenge, which bore the inviting name of Break Our Watermarking System (BOWS), had as its main objective to enlarge the current knowledge on attacks to watermarking systems. In this paper, the main results obtained by the authors when attacking the BOWS system are presented and compared with strategies followed by other groups. Essentially, two different approaches have been followed: exhaustive search of the secret key and blind sensitivity attacks .