KeyNub License Dongle — Gleam Package

import gleam/option.{None}
import gleam/result
import keynub/licdongle

pub fn unlock(sealed: BitArray) -> Result(BitArray, licdongle.DongleError) {
  use d <- licdongle.with_dongle(None)            // first dongle, or Some("serial")
  use _ <- result.try(licdongle.verify_genuine(d)) // Error unless genuine
  use <- licdongle.with_session(d)                // closed on every exit path
  licdongle.app_decrypt(d, sealed)                // <- build the licence check on this
}

Nothing linked. Typed Gleam over the keynub_licdongle Hex package, whose small NIF loads the SDK’s native library at run time, so nothing sits in the path of the check that a customer could substitute. Erlang target; needs Elixir installed to build that dependency, and a C compiler for its NIF.

Setup

gleam add keynub_licdongle_gleam

The package finds keynub_licdongle_flat for your platform in natives/<platform>/ of the KeyNub SDK from the working directory upwards. To ship an application, put the library from the SDK’s natives folder where it runs, or name it before the first call:

let assert Ok(Nil) = licdongle.set_library_path("/opt/keynub/libkeynub_licdongle_flat.so")

KEYNUB_LICDONGLE_FLAT_LIBRARY in the environment does the same. A process loads the library once; loaded_library_path() tells which. On Linux, install the udev rule described in NATIVES.md so the dongle is accessible without root.

Notes

• Every call returns a Result. CallError carries the status (NoDevice, NotGenuine, AuthRequired, …), the raw code, the operation and the library’s detail text; LibraryError reports a library that cannot be loaded.
• Results are records (Info, Genuine, Device, DongleRecord); byte data is BitArray.
• with_dongle and with_session close the dongle and the session on every exit path, crashes included, and return what the body returns. They suit use.
• is_genuine is the boolean form for a gate and fails closed: every failure gives False.
• erase_all_records is separate from erase_record(name): an accidentally empty name must not wipe the dongle.

Read docs/integration-security.md before writing the check. A case licdongle.is_genuine(d) is one conditional branch, and patching one of those in a release is a beginner exercise. Route something the program needs through app_encrypt and app_decrypt, so removing the check removes the data.

Tests

gleam test runs the unit tests. gleam run -m standin runs without a dongle: it compiles a stand-in for the flat C API (bindings/flat/licd_flat.c over bindings/julia/test/stub/licd_stub.c) with the C compiler on the path and exercises every call against it. KEYNUB_SDK_ROOT names the SDK sources when the package is not inside a clone; KEYNUB_LICDONGLE_FLAT_LIBRARY names a compiled stand-in instead. The samples are a Gleam project under samples/gleam (gleam run -m verify_and_read).

Links

• KeyNub License Dongle for Gleam: the product, and how to order one
• Source, samples and issue tracker on GitHub
• Native library for your platform