Minimum encryption settings

UserNeeds changes for IntuneL_Minimumencryptionsettings

Supported on SUPPORTED_Windows7 (defined in the Windows templates)

5568.1000

What it does

This policy setting allows you to set the minimum key length for an encrypted e-mail message. If you enable this policy setting, you may set the minimum key length for an encrypted e-mail message. Outlook will display a warning dialog if the user tries to send a message using an encryption key that is below the minimum encryption key value set. The user can still choose to ignore the warning and send using the encryption key originally chosen. If you disable or do not configure this policy setting, a dialog warning will be shown to the user if the user attempts to send a message using encryption. The user can still choose to ignore the warning and send using the encryption key originally chosen.

What it writes

Hive: HKEY_CURRENT_USER
Registry key: software\policies\microsoft\office\16.0\outlook\security

Why it needs changes for Intune

Policy references a Windows supportedOn definition.
ADMX-INTUNE-WINDOWS-SUPPORTEDON-REFERENCE

Security baselines

Microsoft's Microsoft 365 Apps for Enterprise 2512 sets this to Enabled, in its GPO “MSFT Microsoft 365 Apps v2512 - User”.

Minimum key size (in bits): Set to 168.

Read from the registry.pol files in the baselines' GPO backups, downloaded from Microsoft's Security Compliance Toolkit. All baselines

Options

Option	Type	Registry value	Allowed values
Minimum key size (in bits)Default: 40	Number	`minenckey`	0 to 4294967295

Configure and deploy

Choose a state and the option values; the output below is generated from the template for exactly that.

Enabled · User · template defaults

Registry file (.reg)

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\outlook\security]
"minenckey"=dword:00000028

PowerShell

$ErrorActionPreference = 'Stop'

function Set-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $PropertyType,
        [Parameter(Mandatory = $true)][object] $Value
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        New-Item -Path $Path -Force | Out-Null
    }

    New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}

function Remove-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (Test-Path -LiteralPath $Path) {
        Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
    }
}

function Clear-RegistryKeyValues {
    param(
        [Parameter(Mandatory = $true)][string] $Path
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return
    }

    foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
        Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
    }
}

# Policy: Minimum encryption settings
# Name: L_Minimumencryptionsettings
# Scope: User
# State: Enabled
# Source: outlk16.admx

Set-RegistryValue -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\outlook\security' -Name 'minenckey' -PropertyType 'DWord' -Value 40

The OMA-URI is an inferred ADMX-backed Policy CSP candidate derived from the source ADMX file name and policy name.
Some Microsoft policies use built-in Policy CSP pages whose area names don't match the ADMX file name, so verify the candidate against Microsoft Learn before deployment.

ADMX profile candidate (OMA-URI)

./User/Vendor/MSFT/Policy/Config/ADMX_outlk16/L_Minimumencryptionsettings

ADMX SyncML candidate

<SyncML xmlns="SYNCML:SYNCML1.2">
  <SyncBody>
    <Replace>
      <CmdID>1</CmdID>
      <Item>
        <Meta>
          <Format>chr</Format>
          <Type>text/plain</Type>
        </Meta>
        <Target>
          <LocURI>./User/Vendor/MSFT/Policy/Config/ADMX_outlk16/L_Minimumencryptionsettings</LocURI>
        </Target>
        <Data>&lt;enabled/&gt;
&lt;data id="L_Minimumkeysizeinbits" value="40"/&gt;</Data>
      </Item>
    </Replace>
    <Final/>
  </SyncBody>
</SyncML>

Intune remediation scripts

Detection

$ErrorActionPreference = 'Stop'
$reasons = [System.Collections.Generic.List[string]]::new()

function Test-RegistryValueExists {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return $false
    }

    return $null -ne (Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue)
}

function Test-RegistryValueEquals {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $Kind,
        [Parameter(Mandatory = $true)][object] $Expected
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return $false
    }

    $valueObject = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue
    if ($null -eq $valueObject) {
        return $false
    }

    $actual = $valueObject.$Name
    switch ($Kind) {
        'String' { return [string]$actual -ceq [string]$Expected }
        'ExpandString' { return [string]$actual -ceq [string]$Expected }
        'DWord' { return [uint32]$actual -eq [uint32]$Expected }
        'QWord' { return [uint64]$actual -eq [uint64]$Expected }
        'MultiString' {
            $actualArray = @($actual)
            $expectedArray = @($Expected)
            if ($actualArray.Count -ne $expectedArray.Count) { return $false }
            for ($index = 0; $index -lt $actualArray.Count; $index++) {
                if ([string]$actualArray[$index] -cne [string]$expectedArray[$index]) { return $false }
            }
            return $true
        }
        'Binary' {
            $actualArray = [byte[]]$actual
            $expectedArray = [byte[]]$Expected
            if ($actualArray.Length -ne $expectedArray.Length) { return $false }
            for ($index = 0; $index -lt $actualArray.Length; $index++) {
                if ($actualArray[$index] -ne $expectedArray[$index]) { return $false }
            }
            return $true
        }
        default { return [string]$actual -ceq [string]$Expected }
    }
}

# Policy: Minimum encryption settings
# Name: L_Minimumencryptionsettings
# Scope: User
# State: Enabled
# Source: outlk16.admx

$isMatch = Test-RegistryValueEquals -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\outlook\security' -Name 'minenckey' -Kind 'DWord' -Expected 40
if (-not $isMatch) {
    $reasons.Add('Value mismatch: HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\outlook\security\minenckey') | Out-Null
}

if ($reasons.Count -eq 0) {
    Write-Output 'Compliant'
    exit 0
}

$reasons | ForEach-Object { Write-Output $_ }
exit 1

Remediation

$ErrorActionPreference = 'Stop'

function Set-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $PropertyType,
        [Parameter(Mandatory = $true)][object] $Value
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        New-Item -Path $Path -Force | Out-Null
    }

    New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}

function Remove-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (Test-Path -LiteralPath $Path) {
        Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
    }
}

function Clear-RegistryKeyValues {
    param(
        [Parameter(Mandatory = $true)][string] $Path
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return
    }

    foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
        Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
    }
}

# Policy: Minimum encryption settings
# Name: L_Minimumencryptionsettings
# Scope: User
# State: Enabled
# Source: outlk16.admx

Set-RegistryValue -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\outlook\security' -Name 'minenckey' -PropertyType 'DWord' -Value 40

History 1 retained release

5568.100010 Aug 2026
- Already present in the first release ChangeIntel keeps.

Template

Internal name: L_Minimumencryptionsettings
Namespace: outlk16.Office.Microsoft.Policies.Windows
Template file: outlk16.admx
Release: Microsoft 365 Apps 5568.1000 · file set 8be05d876aae137d…

Definition, editor controls and support

Definition

<policy Area="Security Baseline" AreaCategory="Auth and Encryption" class="User" displayName="$(string.L_Minimumencryptionsettings)" explainText="$(string.L_MinimumencryptionsettingsExplain)" key="software\policies\microsoft\office\16.0\outlook\security" name="L_Minimumencryptionsettings" presentation="$(presentation.L_Minimumencryptionsettings)" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="outlk16.Office.Microsoft.Policies.Windows:L_Cryptography" />
      <supportedOn ref="Microsoft.Policies.Windows:SUPPORTED_Windows7" />
      <elements>
        <decimal id="L_Minimumkeysizeinbits" valueName="minenckey" />
      </elements>
    </policy>

Editor controls

<presentation id="L_Minimumencryptionsettings" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
        <decimalTextBox defaultValue="40" refId="L_Minimumkeysizeinbits" spinStep="0">Minimum key size (in bits):</decimalTextBox>
      </presentation>

Supported platforms and category

outlk16.Office.Microsoft.Policies.Windows:category:L_Cryptography
<category displayName="$(string.L_Cryptography)" name="L_Cryptography" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="outlk16.Office.Microsoft.Policies.Windows:L_Security" />
    </category>
outlk16.Office.Microsoft.Policies.Windows:category:L_MicrosoftOfficeOutlook
<category displayName="$(string.L_MicrosoftOfficeOutlook)" name="L_MicrosoftOfficeOutlook" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
outlk16.Office.Microsoft.Policies.Windows:category:L_Security
<category displayName="$(string.L_Security)" name="L_Security" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="outlk16.Office.Microsoft.Policies.Windows:L_MicrosoftOfficeOutlook" />
    </category>
outlk16.Office.Microsoft.Policies.Windows:unresolved:Microsoft.Policies.Windows:SUPPORTED_Windows7
<unresolved reference="Microsoft.Policies.Windows:SUPPORTED_Windows7" />
outlk16.Office.Microsoft.Policies.Windows:category:L_Cryptography
<category displayName="$(string.L_Cryptography)" name="L_Cryptography" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="outlk16.Office.Microsoft.Policies.Windows:L_Security" />
    </category>
<strings><string id="outlk16.Office.Microsoft.Policies.Windows:L_Cryptography">Cryptography</string></strings>
outlk16.Office.Microsoft.Policies.Windows:category:L_MicrosoftOfficeOutlook
<category displayName="$(string.L_MicrosoftOfficeOutlook)" name="L_MicrosoftOfficeOutlook" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="outlk16.Office.Microsoft.Policies.Windows:L_MicrosoftOfficeOutlook">Microsoft Outlook 2016</string></strings>
outlk16.Office.Microsoft.Policies.Windows:category:L_Security
<category displayName="$(string.L_Security)" name="L_Security" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="outlk16.Office.Microsoft.Policies.Windows:L_MicrosoftOfficeOutlook" />
    </category>
<strings><string id="outlk16.Office.Microsoft.Policies.Windows:L_Security">Security</string></strings>