How to Configure Windows Sandbox Hyper-V Isolated Enclaves via XML in Windows 11

Confidential computing and secure software architectures increasingly rely on hardware-isolated enclaves—such as Virtualization-Based Security (VBS) Enclaves (Virtual Secure Mode) and Intel SGX / AMD SEV extensions. Software enclaves isolate sensitive in-memory computations (such as cryptographic key generation, biometric template matching, and proprietary algorithms) into hardware-shielded memory spaces that even privileged kernel drivers or rogue system administrators cannot inspect. When developing enclave applications or testing zero-trust cryptographic workflows, developers can simulate Hyper-V isolated enclaves inside Windows Sandbox in Windows 11.

Understanding VBS Software Enclaves in Windows

VBS Enclaves operate within Isolated User Mode (IUM) powered by the Windows Hypervisor:

• VBS Enclave DLLs: Specialized dynamic link libraries compiled with the /ENCLAVE linker flag and signed with trusted certificates.
• Enclave Memory Management: Enclave memory is allocated via CreateEnclave() and InitializeEnclave(). The hypervisor masks these physical pages from standard Virtual Trust Level 0 (VTL 0) memory mappings.
• Hardware Memory Protection: Even if malware achieves full Ring 0 kernel execution inside the container, hardware virtualization locks prevent reading or altering enclave RAM.

Authoring the Enclave Provisioning Script

Create a dedicated host folder (e.g. C:\SandboxEnclaveTest) and save a PowerShell provisioning script named InitEnclave.ps1:

# InitEnclave.ps1 - Configure VBS Enclave environment inside Windows Sandbox
Write-Host "Configuring Virtualization-Based Security (VBS) isolated enclave support..." -ForegroundColor Cyan

# 1. Enable VBS Enclave Subsystem in Registry
$vbsPath = "HKLM:SYSTEMCurrentControlSetControlDeviceGuard"
if (-not (Test-Path $vbsPath)) { New-Item -Path $vbsPath -Force | Out-Null }

Set-ItemProperty -Path $vbsPath -Name "EnableVirtualizationBasedSecurity" -Value 1 -Type DWord
Set-ItemProperty -Path $vbsPath -Name "RequirePlatformSecurityFeatures" -Value 1 -Type DWord
Write-Host "VBS core enabled." -ForegroundColor Green

# 2. Verify Enclave API Support via Windows Cryptography Subsystem
Write-Host "Testing Enclave API initialization..." -ForegroundColor Yellow
$enclaveSupport = (Get-ItemProperty -Path "HKLM:SYSTEMCurrentControlSetControlDeviceGuardScenariosHypervisorEnforcedCodeIntegrity" -ErrorAction SilentlyContinue)

Write-Host "Hyper-V isolated enclave testing environment ready." -ForegroundColor Green

Constructing the WSB Configuration File

Create an XML configuration file named EnclaveSandbox.wsb on your desktop:

<Configuration>
  <VGpu>Enable</VGpu>
  <Networking>Default</Networking>
  <MemoryInMB>8192</MemoryInMB>
  <MappedFolders>
    <MappedFolder>
      <HostFolder>C:SandboxEnclaveTest</HostFolder>
      <SandboxFolder>C:EnclaveShare</SandboxFolder>
      <ReadOnly>true</ReadOnly>
    </MappedFolder>
  </MappedFolders>
  <LogonCommand>
    <Command>powershell.exe -NoExit -ExecutionPolicy Bypass -File C:EnclaveShareInitEnclave.ps1</Command>
  </LogonCommand>
</Configuration>

Verifying Enclave Functionality Inside the Sandbox

To verify that software enclaves operate correctly inside Windows Sandbox:

1. Double-click EnclaveSandbox.wsb to boot the virtual container.
2. The PowerShell window executes and initializes VBS settings.
3. Launch an enclave-enabled test binary inside the sandbox.
4. Verify that the application successfully calls IsEnclaveTypeSupported(ENCLAVE_TYPE_VBS) and receives a non-zero success return code.
5. Attempt to inspect enclave memory using user-mode diagnostic utilities; confirm that reading enclave memory pages returns access violation errors, proving hypervisor isolation is active.