Software License Dongle for VB.NET

There is no separate VB binding to learn: KeyNub.LicenseDongle is a .NET assembly, so VB.NET consumes exactly the same package as C# and F#. What differs is the call style, and for interop that difference is worth being deliberate about.

dotnet add package KeyNub.LicenseDongleCode language: Bash (bash)

Reading a license

Option Strict On

Imports KeyNub.LicenseDongle

Using ctx As LicenseDongleContext = LicenseDongleContext.Create()
    Dim devices = ctx.Enumerate()
    If devices.Count = 0 Then
        Console.WriteLine("Please plug in your KeyNub license dongle.")
        Return 0
    End If

    Using dongle As Dongle = ctx.Open()          ' first dongle found
        dongle.VerifyGenuine()                   ' throws unless genuine

        Using session As Session = dongle.OpenSession()
            Dim licence As Byte() = session.ReadRecord("license")
        End Using
    End Using
End UsingCode language: VB.NET (vbnet)

Turn Option Strict on

Some tooling still creates VB projects with Option Strict Off. For code that talks to hardware through a native library, that is exactly the wrong default: a silent narrowing conversion of a byte array, a handle or a length is the class of bug that shows up as corruption at a customer site rather than as a compile error on your machine. The sample sets <OptionStrict>On</OptionStrict> in the project file, and we would recommend the same in yours.

The nested Using blocks are doing real work: each one closes its resource on every exit path, including when an exception unwinds. The dongle driver keeps a small fixed table of open handles, and a leaked one becomes a support call weeks later.

Do not gate on a boolean

A .NET assembly decompiles into readable source, and an If licensed is one IL instruction away from If True. Obfuscation raises the effort; it does not remove the branch. Make the program need something only the dongle can produce:

' Weak -- a branch a patcher removes.
If isLicensed Then EnableFeature()

' Strong -- the values only exist when the dongle does.
Dim coefficients As Byte() = session.AppDecrypt(EncryptedBlobFromInstaller)Code language: VB.NET (vbnet)

Full VB.NET sample on GitHub · the same thing in C# · in F#

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