The crossword solution for the term BRIEF SEC is JIFF, which stands for Joint Intelligence and Fusion Function. This is a joint intelligence function of the United Kingdom's Security and Intelligence Agencies, which was established in 2015. The purpose of the JIFF is to provide a single point of access to intelligence and information from across the UK's security and intelligence agencies. It is designed to improve the sharing of intelligence and information between the agencies, as well as providing a more efficient way of managing intelligence and information.