A security researcher who was set to speak at the Black Hat hacker convention in Las Vegas next week on a previously undiscovered flaw in Apple’s FileVault encryption system has canceled his talk, citing confidentiality agreements with the Cupertino computer maker. Charles Edge, a researcher from Georgia, had been slated to discuss his research on a weakness that could be used to defeat FileVault encryption on the Mac. But sometime last week, Black Hat organizers pulled his name and presentation listing from its schedule of talks. Contacted via cell phone, Edge said he signed confidentiality agreements with Apple, which prevents him from speaking on the topic and from discussing the matter further. Almost every year, much of the drama leading up to and during Black Hat seems to revolve around talks that are canceled or censored at the last minute for various legal reasons. At Black Hat 2007, well-known reverse