ESS PRO · Platform

Communicate across boundaries.
Without opening them.

AMVLET's Cross Domain Solution enables classified and unclassified environments to exchange information with precision — every transfer inspected, sanitised, and policy-controlled before it crosses the line.

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Protocol break architecture One-way or bidirectional Content inspection Hardware-embedded
2
Transfer directions — one-way export, one-way import, or fully bidirectional with independent policies for each direction
0
Direct connections between domains — the protocol break ensures the two networks never share a live network path
100%
Of transfers content-scanned — every message, file, and event inspected before it crosses the domain boundary
Policy rules configurable — bespoke security policy agreed per data controller, updated without service interruption
Live preview

One gateway. Two worlds.

Every transfer between your classified and unclassified environments passes through the Cross Domain Gateway — inspected, sanitised, and logged before delivery.

AMVLET · Cross Domain Gateway
Active
⬆ HIGH SIDE — Classified environment
Active policies
Direction Transfer Content Status
→ OUT brief-14.msg Briefing DELIVERED
← IN status-report-07 Report DELIVERED
→ OUT annex-c.pdf File QUARANTINED
→ OUT directive-445.msg Message DELIVERED
← IN debrief-summary-19 Report DELIVERED
→ OUT raw-comms-log.bin Binary QUARANTINED
← IN field-report-22.msg Report DELIVERED
→ OUT brief-15.msg Briefing DELIVERED
Active policies
1
Content type filter
Messages and documents only
ON
2
Keyword scan
847 blocked terms active
ON
3
Metadata strip
All headers removed on exit
ON
4
Size limit
5 MB per transfer max
ON
Core capabilities

The bridge that never opens.

The Cross Domain Solution connects what must be connected — while structurally preventing what must never cross.

Protocol Break

No direct network path exists between your classified and unclassified environments. The originating connection terminates at the CDS. After inspection, an entirely new connection delivers only the approved, sanitised content to the destination. The two networks never touch.

Content Inspection

Every transfer is scanned against your security policy before crossing the boundary — keywords, file types, size limits, embedded metadata. Content that fails any inspection step is quarantined instantly and logged in full. Nothing reaches the destination domain uninspected.

Directional Control

Configure strictly one-way export, strictly one-way import, or controlled bidirectional exchange — with independent security policies applied to each direction. Most deployments begin with one-way and expand as operational confidence grows.

How it works

Five layers of assurance.

Unlike a conventional firewall, the Cross Domain Solution understands and re-constructs data at the application layer. Here is what that means in practice.

1

Hardware-embedded gateway

The CDS is built to specification and embedded in dedicated hardware that sits at the physical edge of your classified network. This is not a software proxy — it is a purpose-built device. AMVLET works with all major cross-domain hardware vendors, providing the Matrix software layer that runs on top of your hardware infrastructure.

2

Full protocol break

The sending system connects to the CDS — not to the destination. The CDS receives the data, closes the inbound connection, and inspects the content in an isolated environment. If the content is approved, the CDS opens a brand-new, independent connection to the destination and delivers only the sanitised content. No TCP session is ever shared between the two domains.

3

Content scanning and sanitisation

Each transfer passes through a configurable inspection pipeline: keyword scanning, file type verification, structural analysis, metadata stripping, and size enforcement. Transfers that fail any step are quarantined before they reach the destination. The quarantine log is timestamped, attributed, and available for audit — every blocked transfer is a record, not just a rejection.

4

Bespoke security policy

Your CDS operates according to a security policy agreed with your data controller on a case-by-case basis. Every permitted content type, every direction of transfer, every keyword on the blocklist is explicitly defined. Policy updates are deployed through a controlled change process, take effect without service interruption, and every change is logged with a timestamp for audit purposes.

5

Vendor-agnostic compatibility

AMVLET's Cross Domain Solution integrates with all cross-domain hardware vendors. Whether your organisation has existing CDS infrastructure or is commissioning a new deployment, AMVLET provides the Matrix protocol layer that enables your CDS hardware to handle Matrix-based communications natively — with full support for federation, rooms, and events.

Understanding cross domain solutions

Why the most secure environments
need the most precise connections

A classified network is only as secure as its weakest connection to the outside. Cross Domain Solutions replace that weakness with a controlled, policy-enforced channel — not a door left open, but a letter box with a guard.

High-side environments exist because some information is too sensitive to risk on ordinary networks. The intelligence agency. The defence contractor. The financial regulator with systems holding restricted supervisory data. Each operates a classified domain — physically or logically separated from the outside world by design. For decades, that separation meant isolation. If a message needed to cross the boundary, it was printed, reviewed, hand-carried, and re-entered. The risk was managed by removing the connection entirely.

The cost of isolation

Isolation works. It also has costs. Even the most classified environments need to communicate externally — briefings delivered to oversight bodies, status reports shared with liaison teams, field reports ingested from less-secure partner networks. Doing this securely, at the pace modern operations require, is not possible with manual processes. Organisations that cannot move information quickly pay for it in operational speed.

The answer is not to lower the security bar — it is to build a controlled channel precise enough to maintain it. That is what a Cross Domain Solution does.

What a protocol break means in practice

Most people understand a firewall: it looks at the envelope and decides whether to let the packet through. A Cross Domain Solution does something fundamentally different. It opens the envelope, reads everything inside, decides whether the content meets the agreed security policy, and if it does — writes a new envelope on the other side and sends a fresh copy. The original connection is gone. The original packet never crossed. Only approved, sanitised content reached the destination.

No shared path
The two networks share no TCP session. Lateral movement between domains is structurally impossible.
Metadata stripped
All identifying headers, routing information, and embedded metadata are removed before transfer.
Policy-enforced
Every transfer decision is logged. Your security policy is verifiable, attributable, and fully auditable.

In technical terms: when a Matrix message is sent from the classified domain, the Matrix client connects to the CDS — not to the low-side homeserver. The CDS terminates the connection, extracts the message content, runs it through the inspection pipeline. If it passes, the CDS opens a new connection to the low-side homeserver and delivers the approved content as a new Matrix event. The two Matrix deployments are never in direct federation. The protocol break is complete.

Selective communication, not open federation

What a Cross Domain Solution gives classified environments is the ability to define precisely what can move between worlds. Which content types are permitted. Which direction each type can travel. Which senders are trusted. Which words trigger quarantine. Organisations that deploy a CDS gain a controlled, auditable channel — not an open door, but a precisely-specified interface that lets the right information through while keeping everything else contained. For environments that operate at classification level, that precision is the only kind of external communication that is acceptable.

Common questions

Questions before deployment.

What security, compliance, and engineering teams ask when evaluating a Cross Domain Solution for Matrix.

What is a Cross Domain Solution in plain terms?
A Cross Domain Solution allows two separate, isolated networks — typically a classified "high-side" environment and a less-classified "low-side" environment — to exchange specific, approved information. Unlike a firewall, which simply allows or blocks traffic based on network-layer attributes, a CDS performs a complete protocol break: it receives data from one domain, inspects and sanitises it against a bespoke security policy, and delivers only the approved content to the other domain. No direct connection between the two networks ever exists at any point in the process.
What is a protocol break and why does it matter?
A protocol break means that no TCP/IP session is ever shared between the two domains. When a transfer is initiated, the connection from the source terminates at the CDS — the sender never connects to the destination network. After inspection and sanitisation, the CDS opens a completely new, independent connection to the destination and delivers only the approved content. This eliminates the possibility of network-level attacks that exploit live connections — session hijacking, connection traversal, and lateral movement are structurally impossible when there is no shared session to exploit. A firewall or proxy does not provide this guarantee; a CDS does.
How does content inspection work?
Each transfer is evaluated against a configurable inspection pipeline. This typically includes: keyword scanning against a bespoke list of classified or prohibited terms; file type verification to ensure only permitted content formats cross the boundary; metadata stripping to remove identifying headers, routing information, and embedded document properties; size enforcement to prevent bulk data transfer; and structural analysis of file formats to detect disguised content. Transfers that fail any inspection step are quarantined instantly — they are never delivered to the destination — and every quarantine event is logged with attribution and a timestamp for audit purposes.
Can the CDS operate in one direction only?
Yes. The CDS can be configured for strictly one-way data export (high-side to low-side only, with no inbound path at all), strictly one-way data import (low-side to high-side only), or controlled bidirectional exchange with independent security policies applied to each direction. Many high-side environments begin with one-way export only and add bidirectional capability as their operational confidence and policy framework matures. The direction configuration is set at deployment and can be updated through the controlled policy change process.
What hardware does AMVLET work with?
AMVLET's Cross Domain Solution is vendor-agnostic at the hardware layer and integrates with all major cross-domain hardware vendors. AMVLET provides the Matrix protocol software layer — the component that understands Matrix federation, rooms, events, and client-server interactions — which runs on top of the CDS hardware infrastructure. Whether your organisation has existing CDS hardware or requires a new deployment commissioned to specification, AMVLET integrates with it and provides full Matrix compatibility.
How is the security policy agreed and updated?
The security policy is defined in collaboration with your data controller and information security authority before deployment, and agreed on a case-by-case basis reflecting your specific classification requirements and operational use cases. This includes specifying permitted content types, transfer directions, keyword blocklists, metadata handling, and size limits. Policy updates follow a controlled change process: proposed changes are reviewed, approved by the relevant authority, staged, and then deployed — all without service interruption. Every policy change is logged with a timestamp and a record of who authorised it, giving your compliance team a complete audit trail of the policy's history.

Connect the classified
and unclassified.
On your terms.

See how AMVLET's Cross Domain Solution gives your regulated environment a controlled, auditable channel to the outside world — without compromising the integrity of your classified domain.

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