Legitimate "tuff clients" will have a cryptographic signature. On Windows, right-click the .exe → Properties → Digital Signatures tab. Look for "Cloudflare, Inc."
Navigate to the "Download" section of the official site. You will likely see an .exe installer (for Windows) or a .jar file (universal). tuff client download
Run the installer. You will be asked to locate your Minecraft directory if it isn't found automatically. The installer will create a new profile in your Minecraft launcher named "Tuff Client." tuff client download
Includes support for modern 1.21 item textures even when playing on older versions like 1.8 or 1.12. tuff client download