Title Defense of United States Infrastructure Act of 2021 : report of the Committee on Homeland Security and Governmental Affairs, United States Senate to accompany S. 2491 to amend the Homeland Security Act of 2002 to establish the National Cyber Resilience Assistance Fund, to improve the ability of the federal government to assist in enhancing critical infrastructure cyber resilience, to improve security in the national cyber ecosystem, to address Systemically Important Critical Infrastructure, and for other purposes.