KeyNub License Dongle SDK

Host SDK for the KeyNub USB-C license dongle — language bindings and samples over one core C library (keynub_licdongle, prefix licd_) with a stable C ABI. Windows, Linux and macOS, with no driver to install: the dongle is a vendor-defined USB HID device.

Before you write your licensing check, read docs/integration-security.md. The dongle proves a genuine device is attached; it cannot stop an attacker patching the application that asks. An integration that branches on a boolean is bypassed trivially — feed something your application needs through app_encrypt/app_decrypt instead. That document is short, and it is the difference between real protection and a speed bump.

Getting started

1. Pick the native library for your platform from natives/ — NATIVES.md says which file is which.
2. Install the binding for your language, or drop its source into your project.
3. Enumerate, verify, open a session, read your licence data. Each binding's README shows the whole flow in a dozen lines.

The API surface is the same everywhere, because every binding is a thin layer over the same ABI — declared in include/licdongle.h. Learn it once.

Languages

Language	Binding	Sample	Package
C	include/licdongle.h — CMake target keynub::licdongle	samples/c
C++	bindings/cpp — header-only RAII, C++11, CMake target keynub::licdongle_cpp	samples/cpp
flat API	bindings/flat — integer handles, no callbacks	samples/flat	—
C# / VB.NET / F#	bindings/dotnet — KeyNub.LicenseDongle	samples/csharp, samples/vbnet, samples/fsharp
Python	bindings/python — keynub-licdongle, ctypes, plus the licd-tool CLI	samples/python
Java	bindings/java — JNA, Java 17+	samples/java
Delphi / Free Pascal	bindings/delphi	samples/delphi
Visual Basic 6 / VBScript	bindings/com — COM object KeyNub.Dongle	samples/vb6	—
twinBASIC	bindings/com	samples/twinbasic	—
Excel / VBA	bindings/vba	samples/vba	—
MATLAB / Simulink	bindings/matlab — MEX gateway, incl. MATLAB Coder output; runs in GNU Octave	samples/matlab, samples/simulink
Wolfram Language	bindings/wolfram — paclet over ForeignFunctionLoad, flat API	samples/wolfram
LabVIEW	bindings/labview — VI library (LabVIEW 2026, 64-bit) and the import header	samples/labview	—
Node.js / Electron	bindings/nodejs — @keynub/licdongle	samples/nodejs
Go	bindings/go — cgo, errors.Is sentinels	samples/go
Rust	bindings/rust — keynub-licdongle, no dependencies	samples/rust
Ruby	bindings/ruby — stdlib Fiddle, no gems	samples/ruby
PHP	bindings/php — bundled FFI, no PECL module	samples/php
Perl	bindings/perl — FFI::Platypus	samples/perl
Lua	bindings/lua — LuaJIT FFI	samples/lua
Fortran	bindings/fortran — F2003 iso_c_binding	samples/fortran	—
COBOL	bindings/cobol — copybook, GnuCOBOL	samples/cobol	—
Ada	bindings/ada — Alire crate keynub_licdongle, library loaded at run time	samples/ada
Zig	bindings/zig — @cImport compiles the real header	samples/zig	—
Swift	bindings/swift — KeyNubLicDongle, SwiftPM package at the repository root	samples/swift
Dart / Flutter	bindings/dart — keynub_licdongle, dart:ffi	samples/dart
Julia	bindings/julia — ccall, no packages	samples/julia
R	bindings/r — KeyNubLicDongle, a C layer compiled at install	samples/r	—
Haskell	bindings/haskell — keynub-licdongle, pure Haskell over the flat API	samples/haskell
OCaml	bindings/ocaml — keynub-licdongle, ctypes-foreign over the flat API	samples/ocaml
Elixir	bindings/elixir — keynub_licdongle, a small NIF over the flat API	samples/elixir
D	bindings/d — keynub-licdongle, extern(C) over the flat API, dub package at the repository root	samples/d
Crystal	bindings/crystal — keynub_licdongle, function pointers over the flat API, shard at the repository root	samples/crystal	—
Nim	bindings/nim — importc over dynlib	samples/nim

Every sample carries the exact command that builds and runs it in its header comment, including which native library it wants. All of them except Excel/VBA and LabVIEW were compiled and run against a software dongle before release; those two need Excel and a licensed LabVIEW respectively, so they are written against the API and reviewed rather than executed. LabVIEW also has a ready-made VI library (bindings/labview/keynub_licdongle, saved in LabVIEW 2026, 64-bit), whose VIs were run in LabVIEW against the shipped library; Excel ships a .bas rather than an .xlsm so that the code can be reviewed in a diff.

Environments that cannot express the core ABI — LabVIEW, VBA, COBOL — go through a flat companion API (bindings/flat): one self-contained library with integer handles, caller-allocated buffers and no callbacks.

Visual Basic 6 gets a COM object rather than Declare statements for a specific reason: VB6's Declare emits stdcall while the flat API is cdecl. That is harmless in a 64-bit process and a stack-drifting mismatch in a 32-bit one, and VB6 is 32-bit only. Going through an object removes the question — and adds a handle that closes itself and failures that raise with a real Err.Description.

Where the licence check belongs

The shortest useful version of docs/integration-security.md:

// Weak — one patched branch defeats it, in any language.
if (dongle.IsGenuine) enableFeature();

// Strong — the data your program needs only exists with the dongle present.
coefficients = dongle.AppDecrypt(blobShippedWithYourInstaller);

Encrypt the constants, tables, thresholds or key material your application cannot compute. Ship them encrypted. Decrypt them through the dongle at run time. Then removing the check does not unlock the feature — it removes the feature's input.

Trust root

verify_genuine validates the device certificate chain against the KeyNub production root CA, whose public certificate is compiled into the released library — so a substituted device fails verification and your application supplies nothing and manages no root. licd_set_trust_root (or the equivalent on your binding) overrides the built-in root, which only vendor tooling needs.

Security Architecture

The whitepaper behind this SDK covers scope and product boundary, assets, threat model, environment assumptions, security objectives, the mechanisms that meet them, a cryptographic inventory, key management, per-mechanism verification status and the limitations.

• Security architecture — the whitepaper as a page
• KeyNub Security Architecture (PDF) — the dated document
• — the archived record on Zenodo, CC BY-ND 4.0

Cite it as: AB-Tools GmbH (2026). KeyNub USB-C License Dongle: Security Architecture. Rev. 1.1. Zenodo. https://doi.org/10.5281/zenodo.22860069

Licence

Everything in this repository — the bindings, the samples and the C ABI header — is Apache-2.0. See LICENSE, NOTICE and THIRD-PARTY-NOTICES.txt for the dependency licence elections.

The prebuilt native libraries in natives/ are not covered by that licence; their terms are in BINARY-LICENSE.txt. You can use them from an Apache-2.0 binding in a closed-source application either way — that is what they are for.

Security reports: SECURITY.md.

Linux

Install packaging/linux/99-keynub-dongle.rules into /etc/udev/rules.d/ so the device is reachable without root. It is a permission rule, not a driver — nothing is compiled or loaded into the kernel.