Protect a Qt C++ Cross Platform Application

Requirements: QLM Enterprise v15+

Following is a step-by-step procedure to protect a Qt C++ Cross-Platform app. Note that the steps below assume you have a QLM License Server already set up.

1. Launch the QLM Management Console

2. Create a product from the β€œDefine Product” tab or use the Demo 1.0 product if you are evaluating QLM.

3. Go to the "Protect your application tab":

  • Page 1: Select the product to protect and the License Server then click Next

  • Page 2: Select "Other Languages"

  • Page 2: Select "Qt C++ Cross Platform"

  • Page 3: Leave the default settings

  • Page 4: Select the folder where your want to generate the Qt C++ source code and click Save

  • Page 5: Click Finish

4. Add the generated files to your project.

5. If you are building on Windows using ming, you may need to execute the ming tool windeployqt.exe as follows: windeployqt.exe <name of your executable>

6. Install OpenSSL

7. Copy the required binaries to your bin folder. On Windows, you will need:

  • libcrypto-1_1-x64.dll

  • libgcc_s_seh-1.dll

  • libssl-1_1-x64

  • libstdc++-6.dll

  • libwinpthread-1.dll

  • Qt6Core.dll

  • Qt6Gui.dll

  • Qt6Network.dll

  • Qt6Widgets.dll

  • Qt6Xml.dll

7. Review the provided Qt sample to determine how to validate a license at startup. The sample is located in: %Public%\Public Documents\Quick License Manager\Samples\qlmenterprise\Qt

The parameters that may need to be updated in the sample are in mainwindow.cpp:

  • licenseFile: location where the license file will be created

  • URL: URL to the QLM License Server

  • productID: Your product's Product ID as per the Define Products/Product Information tab

  • majorVersion: Your product's Major Version as per the Define Products/Product Information tab

  • minorVersion: Your product's Minor Version as per the Define Products/Product Information tab

  • publicKey: Your product's RSA Public Key as per the Define Products / Encryption Keys tab

In your application, at startup, you must:

  • Create an instance of the QlmLicense class:

    license = new QlmLicense();    
  • Load the license file if it exists:

  • To activate a license, create a function called ValidateLicenseOnServer and call it:

    bool MainWindow::ValidateLicenseOnServer ()
        if (license->Ping (url))
            QString ak = license->getActivationKey();
            QString ck = license->getComputerKey();
            QString cid = license->getComputerID();
            license->activateLicense(url, ak, ck, cid, productID, majorVersion, minorVersion);
            if (license->isLicenseValid(computerId) == false)
                return false;
          return true;

To generate a license key for testing purposes:

  • Go to the Manage Keys tab.

  • Click "Create Activation Key"

  • Select the Product (Demo 1.0 for trials) and click Ok.

  • Copy and Paste the generated Activation Key in the License Wizard launched when your application starts up and follow the steps in the wizard.

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