What is key escrow and why is it controversial?

Key escrow is the practice of storing copies of encryption keys with a trusted third party so that authorized entities, typically law enforcement or the organization, can access encrypted data if the key holder is unavailable or uncooperative. It is controversial because it creates a centralized target for attackers, introduces the risk of unauthorized access, and weakens the fundamental security promise of encryption. Critics argue that any backdoor can be exploited by malicious actors. Proponents argue it enables lawful access for criminal investigations.