Sovereignty in Azure Belgium Central: A Three-Layer Technical Deep Dive

When Belgium Central went live in November 2025, it marked the launch of a new Azure region for Belgian organizations operating in the EU. For many scenarios, it enables customers to run workloads in-country and apply technical controls that can support sovereignty requirements.

But "sovereignty" is one of those words that means different things to different people. So, let's break it down into something more tangible.

In this post, we'll walk through sovereignty in Azure Belgium Central using three standardized technical layers. Think of them as concentric rings of protection around your data:

• Layer 1: Data Residency & Locality. Where your data physically lives and how it behaves during failure.
• Layer 2: Encryption at Rest & In Transit. How data is protected and who holds the keys.
• Layer 3: Confidential Computing. How data is protected while being processed in memory.

Each layer builds on the previous one. Together, they form a comprehensive sovereignty posture. Let's find out what that looks like in practice.

Layer 1: Data Residency & Locality

This layer answers the most fundamental sovereignty question: where is my data, and does it stay there?

In-Country Storage

For regionally deployed Azure services, customer data at rest is stored in the selected Azure region. In Belgium Central, this means data at rest for supported services is stored in Belgium. Microsoft indicates the region’s datacenters are located in the Brussels area. When you deploy a resource with location = "belgiumcentral" in Terraform or location: 'belgiumcentral' in Bicep, you’re selecting that Azure region for the resource.

This matters for organizations bound by Belgian or EU data residency requirements, and it matters for public sector customers who need assurance that sensitive data doesn't cross national borders without explicit action.

Source: Microsoft Digital AmBEtion (microsoft.com/en-be)

Three Availability Zones

Belgium Central supports Availability Zones. Availability Zones are physically separate locations within an Azure region and are designed with independent power, cooling, and networking. This lets you deploy zone-redundant architectures (for example, spreading VMs, databases, and storage across zones) for high availability while keeping resources in the same Azure region.

Availability Zones within a region are connected by high-bandwidth, low-latency networking designed to support zone-redundant services and architectures. Actual latency depends on workload placement and architecture and should be validated for your scenario.

Source: The ABC of Azure Belgium Central (Microsoft Community Hub)

Non-Paired Region: A Sovereignty Feature, Not a Limitation

Azure Belgium Central is a non-paired region. For services that rely on region pairing for automatic geo-replication, behavior and options can differ from non-paired regions. Customers can configure cross-region disaster recovery explicitly and choose a target region based on their requirements.

From a sovereignty perspective, some customers may prefer this model because cross-region replication and secondary data locations are customer-selected when configured. Replication and failover capabilities are service-specific, and customers should confirm the data residency and replication behavior for the services they use.

Depending on the service and redundancy option, some geo-redundant features (for example, Geo-Redundant Storage (GRS) for Azure Storage) may not be available in non-paired regions. Many designs use Zone-Redundant Storage (ZRS) for in-region redundancy across Availability Zones. For cross-region replication, options such as object replication may be used where supported, with the destination region selected by the customer.

Source: Azure region pairs and nonpaired regions (learn.microsoft.com)

What This Means Architecturally

When designing for Belgium Central, customers may consider:

• Intra-region redundancy via Availability Zones (for example, ZRS and zone-redundant deployments), where supported.
• Cross-region disaster recovery when explicitly configured, with a customer-chosen secondary region.
• Replication behavior that is service-dependent; customers should validate which services replicate within a region, across zones, or across regions, and what configuration is required.

Layer 2: Encryption at Rest & In Transit

Layer 1 keeps your data in Belgium. Layer 2 makes sure that even if someone gained physical access to the underlying infrastructure, they'd find nothing readable.

Encryption at Rest: Platform-Managed by Default

By default, all data stored at rest in Azure is encrypted to ensure security and compliance. Storage accounts, managed disks, databases: all use AES-256 encryption with Microsoft-managed keys out of the box. You don't have to configure anything to get this baseline protection.

But for sovereignty scenarios, "Microsoft holds the keys" might not be enough. Data at rest is encrypted by default with platform managed keys but double encryption is possible with an extra layer of encryption with customer managed keys (CMK).

Source: Double encryption in Azure (learn.microsoft.com)

Customer-Managed Keys (CMK): You Hold the Keys

Azure services in Belgium Central support Customer-Managed Keys (CMK) through Azure Key Vault. This shifts key ownership from Microsoft to you. You generate, rotate, and revoke keys on your own schedule. Azure services reference your key in Key Vault for encrypt/decrypt operations, but the key itself is under your control.

This applies to a broad range of services: VM disk encryption, storage account encryption, Azure SQL Transparent Data Encryption, and more.

But not all key storage is created equal. Azure offers three tiers of key management in Belgium Central, and the differences matter for sovereignty:

Source: Azure encryption overview (learn.microsoft.com)

Key Vault Standard: Software-Protected Keys

The entry-level option. Keys are stored encrypted in software, protected by Microsoft's infrastructure, but not in dedicated HSM hardware. This is the entry-level option: software-protected keys stored in a vault, without dedicated HSM hardware. For many general-purpose workloads where regulatory demands don't mandate hardware key protection, Standard is cost-effective and fully functional for CMK scenarios.

Key Vault Premium: HSM-Backed Keys (Multi-Tenant)

Premium includes everything in Standard plus support for HSM-protected keys. When you create an HSM-backed key in a Premium vault, the key material lives inside Microsoft-managed Hardware Security Modules rather than in software. The HSM hardware is shared (multi-tenant, logically isolated per customer), but the key material is processed and stored within certified HSM devices.

Microsoft documentation describes the compliance and validation posture of Key Vault and HSM-backed keys, including FIPS validation details that may vary by hardware generation, region, and service configuration. Customers should refer to the current product documentation and compliance listings for the specific SKU and region in scope.

For many scenarios, Key Vault Premium provides HSM-backed key options in a multi-tenant service model and is priced differently than Key Vault Standard and Managed HSM. The right choice depends on regulatory requirements, operational model, and cost considerations.

Managed HSM: Single-Tenant, Maximum Isolation

For the highest level of key sovereignty, Azure Key Vault Managed HSM provides a single-tenant key management service backed by FIPS 140-3 Level 3 validated hardware. Unlike Key Vault Premium (where HSM-backed keys share a multi-tenant HSM infrastructure), a Managed HSM pool gives you a dedicated, cryptographically isolated HSM environment with your own security domain.

Key facts about Managed HSM that matter for sovereignty:

• Compliance / validation: Managed HSM uses dedicated hardware security modules. Refer to current Microsoft documentation for FIPS validation level and applicability for your region and SKU.
• Regional deployment: Managed HSM is deployed to an Azure region. Customers should validate data residency and any service-specific data handling behavior for their workload and compliance needs.
• Security domain: Customers download and control the security domain (a cryptographic backup of HSM credentials), protected using customer-controlled keys. See product documentation for the shared responsibility model and operational details.
• Access control: Managed HSM provides role-based access controls for key operations. Customers should review the authorization model and administrative boundaries described in the documentation.

Managed HSM has a different pricing and operational model than Key Vault (for example, pool-based billing and additional operational steps). It is typically considered when requirements call for dedicated HSM resources, security domain control, or specific compliance needs beyond a shared HSM service model.

Choosing the Right Tier

Managed HSM is typically considered when requirements call for dedicated HSM resources, security domain control, or administrative separation beyond a shared HSM service model.

Key Vault Standard can be a fit for development/test or scenarios where software-protected keys meet your requirements. Key Vault and Managed HSM capabilities are available in Azure Belgium Central, but customers should verify current product, SKU, and service availability by region and validate service-specific data residency behavior for their workload.

Source: Azure Key Vault Managed HSM overview (learn.microsoft.com), Managed HSM technical details (learn.microsoft.com), About keys (learn.microsoft.com)

Encryption in Transit: MACsec + TLS

On the wire, Azure provides two layers of transit encryption:

1. IEEE 802.1AE MACsec. our documentation describes the use of MACsec on portions of the Azure backbone for in-network encryption on supported links. Availability and coverage can vary by scenario; customers should refer to current documentation for details.
2. TLS. Azure services support TLS for client-to-service connections. Supported TLS versions and configuration requirements vary by service; customers should validate the specific service and endpoint configuration they use.

Together, these mechanisms help protect data in transit at different layers, depending on the service and network path used.

Layer 2 Summary

Trusted Launch and protection of data at rest

Trusted Launch is a security feature available for Azure Virtual Machines that helps protect against advanced threats such as rootkits and bootkits. It enables secure boot and virtual Trusted Platform Module (vTPM) on supported VM sizes, ensuring that only signed and verified operating system binaries are loaded during startup. This provides enhanced integrity for the boot process and helps organizations meet compliance requirements for workloads running in the cloud.

By leveraging Trusted Launch, customers can monitor and attest to the health of their VMs at boot time, making it easier to detect and respond to potential tampering or compromise. The combination of secure boot and vTPM strengthens the security posture of Azure VMs, offering greater protection for sensitive workloads.

Additionally, Trusted Launch strengthens data‑at‑rest protection by isolating encryption keys in a platform‑managed vTPM, binding key release to verified boot integrity, and preventing offline or unauthorized reuse of encrypted disks, even by privileged administrators.

Source: Trusted Launch for Azure virtual machines

Layer 3: Confidential Computing

Layers 1 and 2 protect data where it lives and while it moves. Layer 3 closes the final gap: protecting data while it's being processed in memory.

This is the domain of Azure Confidential Computing, and it's where things get genuinely interesting from a sovereignty perspective. Azure Confidential Computing is designed to help reduce certain operator-access risks by using hardware-backed isolation for data while it is being processed in memory.

Confidential Virtual Machines

Azure Confidential VMs use specialized hardware to create a Trusted Execution Environment (TEE) at the VM level. Two technology families are available:

AMD SEV-SNP (DCasv6 / DCadsv6 / ECasv6 / ECadsv6 series)

These VMs use AMD's Secure Encrypted Virtualization with Secure Nested Paging. The key properties:

• The VM's memory is encrypted with keys generated by the AMD processor. These keys are designed to remain within the CPU boundary.
• The platform is designed to help protect VM memory and state from access by the hypervisor and host management code.
• Supports Confidential OS disk encryption with either platform-managed keys (PMK) or customer-managed keys (CMK), binding encryption to the VM's virtual TPM on supported configurations.
• Each VM uses a virtual TPM (vTPM) for key sealing and integrity measurement.

Intel TDX (DCesv6 / DCedsv6 series)

These VMs use Intel Trust Domain Extensions, which provides full VM memory encryption and integrity protection:

• The entire VM runs inside a hardware-isolated Trust Domain (TD), designed to help protect data in memory from the hypervisor and host management code.
• Memory encryption and integrity are enforced by the Intel CPU using dedicated encryption keys per TD.
• Supports Confidential OS disk encryption (PMK/CMK) and vTPM integration on supported configurations.
• Additional performance characteristics and hardware details vary by VM size and generation; refer to the current VM size documentation for specifics.

The AMD SEV-SNP VM families are currently available in Preview in Azure Belgium Central, with GA planned. The Intel SKU is not currently available in Azure Belgium Central.

Source: About Azure confidential VMs (learn.microsoft.com), DC family VM sizes (learn.microsoft.com), Intel TDX confidential VMs GA announcement (techcommunity.microsoft.com)

Azure Attestation: Trust, but Verify

Confidential computing isn't just about encryption. It's about verifiable trust. Azure Attestation is a free service that validates the integrity of the hardware and firmware environment before your workload runs.

Here's how platform attestation works for AMD SEV-SNP and Intel TDX Confidential VMs:

1. When a confidential VM boots, the hardware generates an attestation report containing firmware and platform measurements (an SNP report for AMD, a TDX quote for Intel).
2. Azure Attestation evaluates this report against expected values.
3. Only if the platform passes attestation are decryption keys released from your Key Vault or Managed HSM.
4. These keys unlock the vTPM state and the encrypted OS disk, and the VM starts.

If the platform does not meet the attestation policy, key release can be blocked and the VM may not start, depending on configuration.

In addition to platform attestation, customers can perform guest-initiated attestation from within the CVM to independently verify the VM's measured hardware and runtime state. This allows applications running inside a confidential VM to obtain an attestation token at runtime, which they can present to relying parties (like a key vault or external service) to prove they are executing in a genuine TEE.

This can help reduce reliance on implicit trust by providing cryptographic evidence about the environment at boot and, where implemented, at runtime.

Azure Attestation availability is region-dependent; customers should verify current availability in Belgium Central and select the appropriate provider configuration for their scenario.

Source: Azure Attestation overview (learn.microsoft.com), Attestation types and scenarios (learn.microsoft.com)

Confidential Computing on AKS

For containerized workloads, Azure Kubernetes Service supports confidential computing through confidential node pools. You can add node pools backed by confidential VMs alongside regular node pools in the same cluster.

You can add AKS node pools using supported confidential VM sizes. In this model, the worker node runs as a confidential VM, so the node’s memory is hardware-protected from the host and hypervisor. Containers scheduled onto that node can run without application refactoring, but the added protection is at the VM/node level. Exact region and SKU availability should be validated for the sizes you plan to deploy.

AKS support for confidential VM sizes today includes AMD SEV-SNP with Intel TDX on the roadmap; customers should validate region and SKU availability for the exact AKS node pool sizes they intend to use.

Azure Attestation can be integrated into confidential computing architectures on AKS to verify the trust state of nodes or workloads before secrets are released. This is typically implemented at the workload or confidential container level and is not enforced automatically for all AKS pods.

Source: Confidential VM node pools on AKS (learn.microsoft.com), Use CVM in AKS (learn.microsoft.com)

The Full Data Protection Chain

When you combine all three layers, the protection chain when using confidential VMs in Belgium Central looks like this:

[Confidential VM boots]

→ Hardware TEE encrypts VM memory (SEV-SNP or TDX, CPU-generated keys)

→ Azure Attestation validates platform report (SNP report or TDX quote)

→ Key Vault (Premium) or Managed HSM conditionally releases disk decryption keys

→ vTPM state unlocked → OS disk decrypted

→ VM starts

→ Data in memory: encrypted and isolated by hardware TEE (Layer 3 – Confidential Compute)

→ Data at rest: encrypted by CMK from Key Vault / Managed HSM (Layer 2 – Encryption)

→ Data in transit: protected using TLS (and MACsec on selected Azure backbone links) (Layer 2 – Encryption)

→ Data stored and processed in Belgium Central where supported and as configured (Layer 1 – Data Residency)

These controls are designed to reduce operator-access risk through hardware-backed isolation, attestation, and customer-controlled key options. The exact protection level depends on the selected service, SKU, region, and configuration

Bringing It All Together

Here's the sovereignty stack for Azure Belgium Central in one view:

Each layer is independently valuable, but the combination can help customers implement stronger technical controls for data residency, encryption, and in-use protection—subject to the specific services, SKUs, regions, and configurations selected.

A Few Honest Caveats

Because I want to keep this honest and useful:

1. Check regional availability for specific SKUs. Availability can vary by region and can change over time. Before finalizing an architecture, confirm that the exact services and SKUs you plan to use are available in Azure Belgium Central (for example, specific confidential VM sizes, Azure Attestation, Managed HSM, and AKS node pool sizes) using the Azure products-by-region information.
2. Sovereignty is not just technical. The layers above cover technical sovereignty, where data is, who encrypts it, and who can access it in memory. Legal sovereignty (jurisdiction, government access requests, contractual commitments) is a separate conversation.
3. Managed HSM has different pricing and operational characteristics. Managed HSM uses pool-based billing and may require additional operational steps compared to Key Vault. Key Vault Premium supports HSM-backed keys in a multi-tenant model, which may be sufficient for many CMK scenarios. Select the option that meets your compliance and operational requirements.
4. Confidential VM capabilities and integrations vary by VM size, generation, and feature. Some scenarios and integrations (for example, certain backup/DR options, live migration behaviors, accelerated networking, or resize paths) may be limited for specific confidential VM offerings. Validate the current limitations and supported features for the exact confidential VM series and region you plan to use, and plan DR based on the services and mechanisms supported for your scenario. These limitations are being actively worked on.

Disclosure: Disaster recovery (DR) design and configuration remain a customer responsibility, including selecting a secondary region and implementing replication, failover, testing, and operational runbooks. Azure service availability and specific features can vary by region, SKU, and deployment model, and may change over time. Replication scope and behavior (in-zone, zone-redundant, regional, or cross-region) are service-specific and depend on the redundancy option selected; validate the data residency and replication details for each service in your architecture.

References

• Microsoft Digital AmBEtion (microsoft.com/en-be)
• The ABC of Azure Belgium Central (Microsoft Community Hub)
• Azure region pairs and nonpaired regions (learn.microsoft.com)
• Azure encryption overview (learn.microsoft.com)
• Double encryption in Azure (learn.microsoft.com)
• Azure Key Vault Managed HSM overview (learn.microsoft.com)
• Managed HSM technical details (learn.microsoft.com)
• About keys (learn.microsoft.com)
• About Azure confidential VMs (learn.microsoft.com)
• DC family VM sizes (learn.microsoft.com)
• Confidential VM FAQ (learn.microsoft.com)
• Intel TDX confidential VMs GA announcement (techcommunity.microsoft.com)
• Confidential VM node pools on AKS (learn.microsoft.com)
• Use CVM in AKS (learn.microsoft.com)
• Azure Attestation overview (learn.microsoft.com)
• Attestation types and scenarios (learn.microsoft.com)
• Azure products by region (azure.microsoft.com)
• Trusted Launch for Azure virtual machines (learn.microsoft.com)