Google › Google Chrome › Cryptography compliance policies

Prefer specific encryption cipher algorithms for TLS

Computer and userIntune-readyPreferSlowCiphers

Supported on Microsoft Windows 7 or later

155.0.8059.85

What it does

This policy configures Google Chrome to order its preferred encryption ciphers in TLS 1.3 to reflect a preference for algorithms that have been approved by a specific compliance regime. Setting this policy does not guarantee that any specific algorithms will be negotiated. This policy exists to allow server operators who wish to support clients with and without compliance requirements to differentiate between those clients, and only use certain non-default algorithms with increased cryptographic strength for those explicitly configured to prefer them. Setting the policy to 'cnsa' configures Google Chrome to prefer ciphers required for compliance with the Commercial National Security Algorithm Suite versions 1.0 and 2.0 (CNSA 1.0 and 2.0). Not setting the policy, or setting it to 'default', configures Google Chrome to use its default ciphers. Setting this policy is not required for security. The default cryptography used by Google Chrome is strong enough to withstand a brute force attack using the entire power of the Sun. Setting this policy will cause Google Chrome to be slower when accessing websites. This policy only affects TLS 1.3 and QUIC; it does not affect earlier versions of TLS. Example value: cnsa

What it writes

Hive: HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER
Registry key: Software\Policies\Google\Chrome

Options

Option	Type	Registry value	Allowed values
Prefer specific encryption cipher algorithms for TLS	Drop-down list	`PreferSlowCiphers`	Prefer ciphers satisfying the requirements of CNSA 1.0 and 2.0`cnsa` Use Google Chrome's default cipher order`default`

Configure and deploy

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

Enabled · Computer · template defaults

Registry file (.reg)

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome]
"PreferSlowCiphers"="cnsa"

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: Prefer specific encryption cipher algorithms for TLS
# Name: PreferSlowCiphers
# Scope: Machine
# State: Enabled
# Source: chrome.admx

Set-RegistryValue -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome' -Name 'PreferSlowCiphers' -PropertyType 'String' -Value 'cnsa'

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.
The generated payload is incomplete because one or more ADMX element values were not supplied: PreferSlowCiphers

ADMX profile candidate (OMA-URI)

./Device/Vendor/MSFT/Policy/Config/ADMX_chrome/PreferSlowCiphers

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: Prefer specific encryption cipher algorithms for TLS
# Name: PreferSlowCiphers
# Scope: Machine
# State: Enabled
# Source: chrome.admx

$isMatch = Test-RegistryValueEquals -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome' -Name 'PreferSlowCiphers' -Kind 'String' -Expected 'cnsa'
if (-not $isMatch) {
    $reasons.Add('Value mismatch: HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\PreferSlowCiphers') | 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: Prefer specific encryption cipher algorithms for TLS
# Name: PreferSlowCiphers
# Scope: Machine
# State: Enabled
# Source: chrome.admx

Set-RegistryValue -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome' -Name 'PreferSlowCiphers' -PropertyType 'String' -Value 'cnsa'

History 1 retained release

155.0.8059.8519 Oct 2026
- Already present in the first release ChangeIntel keeps.

Template

Internal name: PreferSlowCiphers
Namespace: Google.Policies.Chrome
Template file: chrome.admx
Release: Google Chrome 155.0.8059.85 · file set 1f03ffd12695d620…

Definition, editor controls and support

Definition

<policy class="Both" displayName="$(string.PreferSlowCiphers)" explainText="$(string.PreferSlowCiphers_Explain)" key="Software\Policies\Google\Chrome" name="PreferSlowCiphers" presentation="$(presentation.PreferSlowCiphers)" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Google.Policies.Chrome:CryptographyCompliance" />
      <supportedOn ref="Google.Policies.Chrome:SUPPORTED_WIN7" />
      <elements>
        <enum id="PreferSlowCiphers" valueName="PreferSlowCiphers">
          <item displayName="$(string.PreferSlowCiphers_CNSA)">
            <value>
              <string>cnsa</string>
            </value>
          </item>
          <item displayName="$(string.PreferSlowCiphers_Default)">
            <value>
              <string>default</string>
            </value>
          </item>
        </enum>
      </elements>
    </policy>

Editor controls

<presentation id="PreferSlowCiphers" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions"><dropdownList refId="PreferSlowCiphers">Prefer specific encryption cipher algorithms for TLS</dropdownList></presentation>

Supported platforms and category

Google.Policies.Chrome:category:CryptographyCompliance
<category displayName="$(string.CryptographyCompliance_group)" name="CryptographyCompliance" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Google.Policies.Chrome:googlechrome" />
    </category>
Google.Policies.Chrome:category:googlechrome
<category displayName="$(string.googlechrome)" name="googlechrome" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Google.Policies:Cat_Google" />
    </category>
Google.Policies.Chrome:definition:SUPPORTED_WIN7
<definition displayName="$(string.SUPPORTED_WIN7)" name="SUPPORTED_WIN7" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Google.Policies:category:Cat_Google
<category displayName="$(string.google)" name="Cat_Google" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Google.Policies.Chrome:category:CryptographyCompliance
<category displayName="$(string.CryptographyCompliance_group)" name="CryptographyCompliance" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Google.Policies.Chrome:googlechrome" />
    </category>
<strings><string id="Google.Policies.Chrome:CryptographyCompliance_group">Cryptography compliance policies</string></strings>
Google.Policies.Chrome:category:googlechrome
<category displayName="$(string.googlechrome)" name="googlechrome" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="Google.Policies:Cat_Google" />
    </category>
<strings><string id="Google.Policies.Chrome:googlechrome">Google Chrome</string></strings>
Google.Policies.Chrome:definition:SUPPORTED_WIN7
<definition displayName="$(string.SUPPORTED_WIN7)" name="SUPPORTED_WIN7" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Google.Policies.Chrome:SUPPORTED_WIN7">Microsoft Windows 7 or later</string></strings>
Google.Policies:category:Cat_Google
<category displayName="$(string.google)" name="Cat_Google" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Google.Policies:google">Google</string></strings>