Article 24 of the EU General Data Protection Regulation requires a controller to implement appropriate technical and organizational measures and to be able to show that those measures fit the risk. It is an accountability rule: security is not judged only by whether a breach happened, but by whether the controller acted reasonably, proportionately, and with documented care.
In cyber security, Article 24 matters because it turns controls into evidence. Access control, patch management, supplier oversight, incident logs, and risk assessments can all demonstrate that a program was designed responsibly. Attackers may still succeed, but a well-prepared organization can show that it reviewed threats, selected suitable safeguards, and adapted them to the data and environment. Weak documentation, vague policies, or outdated controls make that defense much harder.