Defining zero trust – and how it impacts physical security

Traditional security was built for a different world: fixed offices, owned servers, and defined network borders. Keep threats out, let trusted users in, and allow internal systems to communicate freely. That model no longer holds. Zero Trust operates on a single principle: never trust, always verify. Every access request is continuously authenticated based on identity, device health, location, and behaviour, regardless of where the request originates. This shifts security away from perimeter reliance toward ongoing validation of every interaction. Single-factor credentials give way to multi-factor authentication combining biometrics, mobile credentials, and role-based access windows. Physical entry points become active verification layers, with anti-passback and anti-tailgating controls enforcing one authenticated individual per event. Cameras, sensors, and access readers integrate to detect behavioural anomalies in real time. If an account is compromised in the IT environment, access to secure facilities restricts automatically. Zero Trust makes physical security identity-driven, context-aware, and continuously verified.

Zero trust is a security model built on a simple principle: never trust, always verify. Rather than assuming that a user, device or system is safe because it sits inside the corporate perimeter, zero trust requires continuous authentication, strict least-privilege access and ongoing risk evaluation. It assumes breach as a starting point — and designs controls accordingly. In the context of physical security, this represents a significant mindset shift. Traditionally, organisations have relied on perimeter-based thinking: once an individual is inside the building, they are broadly trusted. Zero trust challenges that assumption. Access must be verified not just at the front door, but throughout the facility — with permissions limited strictly to the areas required for a person’s role. For physical access control, this means stronger credential assurance, enhanced monitoring, and better anomaly detection. It also means breaking down the historical silos between physical and IT security. Doors, readers, and identity systems should not operate independently of digital access controls; they should form part of a unified verification model. Technologies such as FIDO-based authentication or PKI credentials can be combined with physical access data to verify that the individual has legitimately entered the building. If a badge is used to open a secure door, the system can correlate that event with a subsequent IT login.

Zero trust is about removing assumptions from security. Access is no longer based on a one-time credential check. It requires continuous validation of users, devices, and behaviour, regardless of where access occurs. In physical security, this shifts the focus away from static controls like badges alone toward a more dynamic, real-time understanding of activity. Organisations need greater visibility into not just who is entering a space, but whether their actions align with expected behaviour. Video plays a critical role in enabling this insight. When combined with analytics and integrated systems, it provides the context needed to validate events, detect anomalies, and support faster, more confident decision-making. This shift is driven by evolving threats and rising expectations. Security teams are being asked to deliver more intelligence, reduce uncertainty, and operate proactively bringing physical and cyber strategies closer together.

Zero Trust assumes no user, device, system, or AI agent should be inherently trusted. In an agentic AI world, where autonomous systems take actions on behalf of users, continuous validation becomes even more critical. Every request, decision, and action must be verified in real time to prevent misuse, drift, or compromise. In physical environments, security is moving beyond perimeter-based models toward persistent validation. Biometrics, smart credentials, and real-time monitoring ensure identities are continuously authenticated, not just at entry. Digitally, this extends to AI agents and automated workflows. Controls like multi-factor authentication, identity and access management, and segmentation must now validate not only human users but also machine-driven actions and delegated authority. Together, these strategies create a unified approach where every person, device, and interaction is actively evaluated. As biometric threats and social engineering grow more complex, the need to “never trust, always verify” is more important than ever.

Zero Trust is a cybersecurity approach based on a simple principle: never assume trust, and always verify. Every user, device, application, and system interaction must be authenticated, authorised, and continuously validated before access is granted. That applies whether the request comes from inside the corporate network or from outside it. For physical security, this has become increasingly important as systems, devices, and cloud services are now connected to broader IT environments. Physical security systems must be treated as part of the organisation’s overall cyber risk profile. A Zero Trust approach helps reduce that risk by limiting access to only what each person or device needs, segmenting resources to restrict lateral movement, encrypting data, and continuously monitoring activity for unusual behaviour. This approach also puts more scrutiny on technology companies. Physical security vendors need to show that cybersecurity is built into their products and processes, with strong identity controls, secure cloud practices, regular updates, and tools that help customers detect and respond to risk.

Zero trust replaces the traditional assumption that users and devices inside the firewall can be trusted. Instead of assuming anything inside the perimeter is safe, every user, device, and data flow must keep proving it belongs, through verified identity, least-privilege access, encrypted communication, and constant monitoring. For physical security, that's a big shift. Cameras, access controllers, and NVRs often get dropped onto flat networks and forgotten. Under zero trust, they become active participants. Each device presents a cryptographic identity, talks only to authorised endpoints, and gets watched for behavioural drift. At i-PRO, we build this into every camera model. Our cameras use an NXP EdgeLock secure element certified to FIPS 140-3 Level 3, with secure boot, firmware signature verification, pre-installed GlobalSign certificates, and 802.1X. A camera isn't just a sensor. It's a verifiable node. Zero trust turns physical security devices from soft targets into a hardened part of your security posture.

Zero Trust is a security model that removes implicit trust and requires every access request to be explicitly verified based on identity, context and policy. It also requires that this trust be continuously re-evaluated rather than granted once. In the logical access world, this is already standard practice. Modern systems no longer assume a successful login or network location is sufficient, instead validating user identity, device posture and risk signals throughout a session. When you apply this to physical security, Zero Trust challenges the long-standing reliance on static, badge-based access. Rather than treating a credential as permanently trusted, access decisions become more dynamic and identity-driven, considering who the person is, how they are authenticating and whether current conditions still justify access. This aligns physical access control more closely with modern cybersecurity principles and supports stronger convergence between physical and logical security systems.

Zero trust is a cybersecurity framework built on the principle of “never trust, always verify,” meaning that no user, device, or system is inherently trusted—whether inside or outside the network. Instead, every access request is continuously authenticated, authorized, and limited to only what’s necessary. In physical security, this approach has fundamentally reshaped how connected devices like cameras, access control systems, and intercoms are deployed and managed. As these devices become IP-based and integrated into enterprise networks, they are treated as potential vectors for lateral movement and internal compromise, rather than inherently trusted infrastructure. Zero trust requires each device to prove its identity, use encrypted communications, and operate with least-privilege access, limiting the potential for lateral movement. The result is a more resilient security posture. Even if a device or credential is compromised, micro-segmentation and continuous verification help contain threats, ensuring physical security systems don’t become cybersecurity liabilities.