sentences:  Concerns about the approach included its similarity to past systems that failed, such as CSS, and the inability to preserve security against attacks that compromise large numbers of players.Jon Lech Johansen, who was part of the team that circumvented CSS, said he expected AACS to be cracked by the end of 2006 or the beginning of 2007.In late 2006, security expert Peter Gutmann released ""A Cost Analysis of Windows Vista Content Protection"", a technical paper criticizing the implementation of various content protection technologies in Windows Vista.