Since appearing in devices in 2006, several successful attacks have been made on the format. The first known attack relied on the trusted client problem. In addition, decryption keys have been extracted from a weakly protected player (WinDVD). Notably, a "Processing Key" was found that could be used to decrypt all HD content that had been released at the time. The processing key was widely published on the Internet after it was found and the AACS LA sent multiple DMCA takedown notices with the aim of censoring it. This caused trouble on some sites that rely on user-submitted content, like Digg and Wikipedia, when administrators tried to remove any mentions of the key.