Security & compliance guide
Secure visualisation infrastructure for controlled and classified environments.
Standard AV designs frequently rely on general-purpose hardware, unmanaged display interfaces and connectivity features that are not always appropriate for controlled environments.
At a glance
This guide explains when AV becomes part of the security architecture and routes readers to the relevant Secure AV, HDMI Data Blocker and control room pages.
Secure AV hub
A gateway for secure visualisation concepts, interface control, no-wireless design and controlled AV architecture.
Architecture choices
Closed loop, air-gapped, secure AV-over-IP and multi-classification approaches are linked to the relevant deeper pages.
Hardware controls
HDMI Data Blocker and MERLIN are introduced as UK-manufactured products supporting secure AV use cases.
Guidance routes
Focused guidance areas help buyers move from a security question to the right capability or product page.
Why standard AV approaches fall short in secure environments
In environments where the security of information matters - whether that is a defence command room, a government operations centre, a regulated financial environment or a controlled collaboration space - the AV layer needs the same rigour applied to the rest of the system.
Standard AV designs typically optimise for flexibility and ease of use - wireless presentation, consumer HDMI connectivity, cloud-managed control systems and automatic device negotiation. These features are appropriate in many environments. They are not always appropriate in controlled ones.
Wireless interfaces increase the attack surface where they are not required. Unmanaged HDMI, DisplayPort and USB paths create uncertainty about how systems communicate beyond the visible video signal. Consumer-grade control systems may introduce network dependencies or remote access capabilities that are inconsistent with the requirements of the environment.
What secure AV architecture addresses
Security and compliance requirements affect the way AV interfaces, signal paths, networks, products and deployment processes are designed.
HDMI interface control
Unmanaged HDMI connections can carry non-video communication channels between connected systems. Hardware-enforced interface control removes that path without relying on software policy or user behaviour.
View related pageClosed loop and air-gapped AV
Completely isolated AV networks with no external network connection - appropriate for environments where unintended connectivity cannot be accepted and where the system boundary needs to be clearly defined.
View related pageNo-wireless architecture
AV systems designed without WiFi or Bluetooth where the environment requires wired-only, controlled connectivity. Wireless presentation and consumer connectivity features are removed by design.
View related pageMulti-classification display environments
Operational rooms handling information at different security levels - with physical and logical separation of signal paths, dedicated processing per domain and hardware-enforced interface control.
View related pageSecure by Design alignment
AV system architecture aligned with Secure by Design principles - minimising attack surface, enforcing deterministic behaviour, avoiding unnecessary connectivity and using hardware controls where software policy alone is insufficient.
View related pageSupply chain and country of origin
Where TAA compliance or specified country-of-origin requirements form part of the procurement specification, Harp Visual considers these requirements during product selection. UK-manufactured products are available.
View related pageSecure by Design in AV environments
Secure by Design is an approach to system architecture that builds security in from the outset - rather than applying controls to an existing design. In AV terms, this means starting with the security requirements of the environment and designing the signal paths, interfaces, hardware and connectivity accordingly.
For Harp Visual, this means applying a small number of practical design principles consistently across secure and managed AV environments.
Minimise attack surface
Remove connectivity features that are not required by the operational model - wireless interfaces, consumer control protocols and unmanaged display connections. If it is not needed, it is not present.
Hardware-enforced controls
Where software policy alone is insufficient, use hardware-based controls that operate deterministically and cannot be bypassed through software configuration or user action.
Defined signal boundaries
Every signal path has a defined source, route and destination. Unintended communication between systems is reduced through the architecture, not managed only through procedure.
Deterministic behaviour
Systems behave the same way every time, regardless of what devices are connected or what users do. Predictable operation is a security property, not just a usability one.
Controlled deployment
Installation delivered with method statement, risk assessment, pre-configuration completed off-site, post-installation documentation and structured handover. The deployment process reflects the security requirements of the environment.
UK-manufactured products for secure AV environments
Harp Visual designs and manufactures two products specifically for secure and controlled AV environments. Both are designed and built in the UK.
HDMI Data Blocker
Hardware-enforced unidirectional video interface security device. Prevents non-video HDMI communication channels from passing between connected systems. The device does not require user-installed software, a network connection or user-managed configuration. The HDMI Data Blocker circuit design has undergone technical security evaluation activity within UK Government environments. Deployed in UK Government and MOD environments to support secure AV use cases. Available direct and through UK government and defence procurement frameworks. Further documentation is available to qualified organisations through controlled channels on request.
View productMERLIN Video Wall Processor
UK-designed and manufactured video wall processor for 24/7 operational control rooms and command environments. Drives up to 64 screens. Dual redundant power. Hot-swap capability. AV-over-IP via IPX variant. Deployed in defence, government, transport and utilities operational environments.
View productGuidance areas
Focused guidance for teams assessing secure AV architecture, controlled display interfaces and mission-critical visualisation requirements.
Prevent HDMI data leakage
Problem-focused guidance on unmanaged HDMI connections, what communication channels the interface carries, and how hardware-enforced interface control addresses the risk.
AvailableNo-wireless AV architecture
Guidance for AV environments where wireless interfaces are removed or restricted to support controlled connectivity - including what this means in practice for system design and equipment selection.
Coming
Multi-classification display environments
Considerations for rooms where different information handling levels, users or display workflows require controlled separation - including architecture options and hardware controls.
Coming
Closed loop and air-gapped AV systems
Guidance for AV systems that need to support separated networks, sources or operational domains with no external network connectivity.
Coming
Supply chain and country of origin
Deployment considerations where specified country-of-origin requirements or TAA compliance form part of product or system selection.
Coming
BS EN 50518 control room AV
Control room AV considerations for environments working around BS EN 50518 requirements and operational resilience standards.
Coming
Common questions
Direct answers for teams assessing secure visualisation, compliance constraints and controlled AV architecture.
What is secure visualisation infrastructure?
Secure visualisation infrastructure is the AV layer used to display and route operational information while controlling signal paths, interface behaviour and hardware architecture. It applies to command and control rooms, operations rooms, secure briefing spaces and other environments where the security of information handled in the room extends to the AV systems that present it.
Why remove WiFi and Bluetooth from AV systems?
Wireless interfaces can increase the attack surface in environments where controlled, wired-only connectivity is a security requirement. A no-wireless AV architecture reduces this exposure by design - not by policy. AV systems can be delivered without WiFi or Bluetooth where the environment requires it, including video conferencing, presentation and display systems.
What does TAA or country of origin mean for AV?
TAA (Trade Agreements Act) and specified country-of-origin requirements relate to product sourcing and procurement constraints relevant to certain government and defence programmes. Harp Visual considers these requirements during product selection where they form part of the specification - including specifying UK-manufactured products where appropriate. Suitability depends on the specific programme requirements.
Why are unmanaged display interfaces a concern in secure environments?
HDMI, DisplayPort and USB interfaces carry more than the visible signal they are associated with. These interfaces include communication channels used for device identification, control and negotiation. In secure environments, these channels can represent an unintended communication path between connected systems - one that may sit outside the logical security controls applied to the network and endpoint estate. Hardware-enforced interface control addresses this at the physical level.
What is Secure by Design in an AV context?
Secure by Design in AV means building security requirements into the system architecture from the outset - defining signal paths, interface controls, hardware selection and connectivity based on the security requirements of the environment. This includes minimising attack surface, using hardware controls where software policy alone is insufficient, ensuring deterministic system behaviour and delivering with appropriate documentation and assurance evidence.
What assurance documentation is available for the HDMI Data Blocker?
The HDMI Data Blocker circuit design has undergone technical security evaluation and assurance processes within UK Government environments. Deployed in UK Government and MOD environments to support secure AV use cases. Further documentation is available to qualified organisations through controlled channels on request. Public materials are intentionally limited to protect operational security.