A security architecture based on the principle of "never trust, always verify" — eliminating implicit trust based on network location and requiring continuous verification of every user, device, and connection.
Zero trust challenges the traditional network security model where everything inside the firewall is trusted. In a zero trust architecture, no user, device, or network connection is trusted by default — regardless of whether they are inside or outside the corporate network. Every access request must be authenticated (who are you?), authorized (should you have access?), and encrypted (is the connection secure?) before access is granted. Trust is never assumed; it is continuously evaluated based on identity, device health, location, behavior, and risk signals.
The core principles of zero trust are: verify explicitly (authenticate and authorize based on all available data points), use least privilege access (provide the minimum access needed for the current task), and assume breach (design controls assuming an attacker is already inside). These principles, formalized by NIST SP 800-207, are implemented across five pillars: Identity, Devices, Networks, Applications and Workloads, and Data.
Zero trust is particularly effective against ransomware because ransomware thrives on implicit trust. In traditional networks, a compromised user account can move laterally to any system, access any file share, and escalate to domain admin — all because the network trusts internal traffic by default. Zero trust eliminates this implicit trust: compromised credentials alone are insufficient without device compliance, MFA verification, and behavioral analysis. Micro-segmentation prevents lateral movement, and least privilege access limits the blast radius of any compromise.