Facebook is scrambling to add safeguards against abuse of user data as it reels from backlash over the Cambridge Analytica scandal. Now TechCrunch has learned Facebook will launch a certification tool that demands that marketers guarantee email addresses used for ad targeting were rightfully attained. This new Custom Audiences certification tool was described by Facebook representatives to their marketing clients, according to two sources. Facebook will also prevent the sharing of Custom Audience data across Business accounts. This snippet of a message sent by a Facebook rep to a client notes that “for any Custom Audiences data imported into Facebook, Advertisers will be required to represent and warrant that proper user content has been obtained.” Once shown the message, Facebook spokesperson Elisabeth Diana told TechCrunch “ I can confirm there is a permissions tool that we’re building.” It will require that advertisers and the agencies representing them pledge that “I ...