sentences:  This would require that content distributors do not permit their content to be played on PCs without trusted computing technology, by not providing the companies making software players for non-trusted PCs with the needed encryption keys.On 16 April 2007, the AACS consortium announced that it had expired certain encryption keys used by PC-based applications.Patches were available for WinDVD and PowerDVD which used new and uncompromised encryption keys.