The ISPS Code is a comprehensive set of measures developed by the IMO to enhance maritime security. It was developed in response to terrorist attacks like 9/11 and the attack on the Limburg tanker. The ISPS Code has two parts - Part A which contains mandatory requirements for ships and port facilities, and Part B which contains guidance. Key elements of the ISPS Code include conducting vessel and facility security assessments to identify vulnerabilities, developing security plans, appointing security officers, controlling access to restricted areas, conducting drills and exercises, and setting security levels. Contracting governments are responsible for oversight of the ISPS Code and can authorize Recognized Security Organizations to assist with certain activities.