A register is a controlled log used to record and manage important security items such as risks, incidents, exceptions, assets, or compliance evidence. Unlike a casual list, a register has ownership, update rules, and a defined purpose, so it can be used as trusted evidence in governance and audits.
In cyber security, registers matter because they connect policy to action. A risk register shows what threats have been identified and who is handling them; an incident register preserves what happened, when it was reported, and how it was resolved; an evidence register helps prove that controls were tested or approved. Defenders use registers to track accountability and prioritize work, while attackers often expose gaps when records are incomplete, outdated, or inconsistent with inventories and procedures. A well-maintained register helps an organization spot drift before it becomes a security failure.