Information Analysis and Infrastructure Protection Directorate. The division of the U.S. Department of Homeland Security responsible for analyzing intelligence information gathered from the Central Intelligence Agency, the Defense Intelligence Agency, the Federal Bureau of Investigation, the National Security Administration, and other sources, and for issuing warnings about threats of terrorist attack. • The unit is also charged with evaluating weaknesses in the nation’s infrastructure and recommending ways to reduce vulnerability to attacks. — Abbr. IAIP.