Zero trust architecture is a security model built on the idea that nothing is trusted by default, even if it is inside the corporate network. Every access request must be verified using identity, device health, context, and policy before it is allowed. This matters because modern systems are spread across cloud services, remote users, APIs, and partners, so old network boundaries no longer protect assets reliably.
In practice, zero trust reduces the impact of stolen credentials, rogue devices, and compromised services. Attackers often try to move laterally after gaining one foothold; zero trust makes that harder by enforcing least privilege, strong authentication, device checks, segmentation, and continuous revalidation. Defenders also use detailed logging and conditional access to detect suspicious behavior and block access when risk changes. It is not a single product, but a design approach that improves resilience across distributed environments.