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Enable strong Diffie-Hellman key requirement

Overview​

About this script

This script improves your privacy on Windows.

These changes use Windows system commands to update your settings.

This script improves your security by setting the Diffie-Hellman 1 2 3 key exchange to a minimum of 2048 bits. This is a secure way to exchange keys over public networks.

This script only affects the SSL/TLS handshake process. The SSL/TLS handshake is a key part of establishing a secure connection over the internet. By disabling this weak algorithm, the script improves the security of the connection.

By default, modern Windows versions use a 2048-bit size for Diffie-Hellman key exchanges 1. Sizes under 1024 bits are considered weak 4 5. NIST in USA 4 and Federal Office for Information Security (BSI) in Germany 3 disallows usage of sizes under 2048 bits. NSA (National Security Agency) recommends at least 3072 bits 6.

This script hardens your system's security by using keys of adequate strength, following best practices.

Caution
  • Using bigger keys increases security but may not work with some old or less secure apps.
  • This can make your device slower and drain the battery faster.

This script uses Batch (batchfile) scripting language.

Safe for General Use

This script is recommended for all users. It helps to improve privacy without affecting stability.

Implementation Details

  • Language: batch

  • Required Privileges: Administrator rights

  • Compatibility: Windows only

  • Reversibility: Can be undone using provided revert script

Explore Categories​

This action belongs to Enable strong secret key requirements category. This category contains scripts that enhance system security by implementing stronger encryption key lengths. Stronger keys help prevent unauthorized data access and potential leaks. These scripts aim to protect your data when sent over network (Internet), making sure your security matches up... Read more on category page ▶

Apply now​

Choose one of three ways to apply:

  1. Automatically via privacy.sexy: The easiest and safest option.
  2. Manually by downloading: Requires downloading a file.
  3. Manually by copying: Advanced flexibility.

Alternative 1. Apply with Privacy.sexy​

privacy.sexy is free and open-source application that lets securely apply this action easily.

Open privacy.sexy

You can fully restore this action (revert back to the original behavior) using the application.

privacy.sexy instructions
  1. Open or download the desktop application
  2. Search for the script name: Enable strong Diffie-Hellman key requirement.
  3. Check the script by clicking on the checkbox.
  4. Click on Run button at the bottom of the page.

Alternative 2. Download​

Irreversible Changes

This script is irreversible, meaning there is no straightforward method to restore changes once applied. Exercise caution before running, restoring it may not be possible.

  1. Download the script file by clicking on the button below:

    Download script

  2. Run the script file by clicking on it.

Download revert script​

This file restores your system to its original state, before this script is applied.

Download restore script

Alternative 3. Copy​

This is for advanced users. Consider automatically applying or downloading the script for simpler way.

  1. Open Command Prompt as administrator.
HELP: Step-by-step guide

  1. Click on Start menu

  2. Type cmd

  3. Right click on Command Prompt select Run as administrator

  4. Click on Yes to run Command Prompt

Animation showing how to open terminal as administrator on Windows 11

  1. Copy the following code:
Code to apply changes
:: Require "Diffie-Hellman" key exchange algorithm to have at "2048" least bits keys for TLS/SSL connections
:: Set the registry value: "HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman!ServerMinKeyBitLength"
PowerShell -ExecutionPolicy Unrestricted -Command "$registryPath = 'HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman'; $data = '2048'; reg add 'HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman' /v 'ServerMinKeyBitLength' /t 'REG_DWORD' /d "^""$data"^"" /f"
:: Set the registry value: "HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman!ClientMinKeyBitLength"
PowerShell -ExecutionPolicy Unrestricted -Command "$registryPath = 'HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman'; $data = '2048'; reg add 'HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman' /v 'ClientMinKeyBitLength' /t 'REG_DWORD' /d "^""$data"^"" /f"
  1. Right click on command prompt to paste it.
  2. Press Enter to apply remaining code.

Copy restore code​

Copy and run the following code to restore changes:

Revert code
:: Restore key size requirement for "Diffie-Hellman" for TLS/SSL connections
:: Delete the registry value "HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman!ServerMinKeyBitLength"
PowerShell -ExecutionPolicy Unrestricted -Command "reg delete 'HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman' /v 'ServerMinKeyBitLength' /f 2>$null"
:: Delete the registry value "HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman!ClientMinKeyBitLength"
PowerShell -ExecutionPolicy Unrestricted -Command "reg delete 'HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman' /v 'ClientMinKeyBitLength' /f 2>$null"

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