From the Executive Summary: "The Department of Justice (DOJ) has publicly noted that the prevalence and sophistication of encryption and the use of new applications (apps) are degrading the ability to collect information pertinent to national security. More specifically, these technologies are diminishing both law enforcement and the Intelligence Community's (IC) ability to lawfully intercept data in motion as well as access stored data. This issue is commonly referred to as the 'going dark' problem. The challenges going dark presents extend beyond the government's requirements. Going dark also touches on privacy issues, technical limitations, legislative shortcomings, and other considerations. This paper presents the findings of a team of public and private sector analysts focused on the going dark problem and its attempt to collectively address the national security concerns resulting from barriers to data collection."
U.S. Department of Homeland Security: https://www.dhs.gov/