Using LexActivator with C, C++ and Objective C

First of all, login to your Cryptlex account and download the LexActivator library for Windows, macOS or Linux:

• Download LexActivator for Windows

• Download LexActivator for macOS

• Download LexActivator for Linux

The above download package contains the library (shared as well as static) which you will be using to add licensing to your app.

Adding licensing to your app

After you've added a product for your app in the admin portal, you will need to do the following things:

• Note the product id for the product (from the actions menu in the table).

• Download the Product.dat for the product (from the actions menu in the table).

• Download the example project from Github.

Product.dat contains product data that is used by LexActivator. The product id is the identifier of your product that is to be used in the code.

Adding the library to your app

LexActivator example project for C contains the LexActivator.h header file. In addition to that, it includes the LexActivator.lib file required in the case of Windows. It contains all the LexActivator API functions needed to add licensing to your app.

Depending on the platform you are targeting (x86 or x64) you need to link the respective LexActivator.dll with your application.

LexActivator has a dependency on VS2015 runtime on Windows. On the target machines where you will deploy your app, you can install the VS2015 runtime, if not present, using the link: https://www.microsoft.com/en-in/download/details.aspx?id=48145

Setting product.dat file and product id

The first thing you need to do is either embed the Product.dat file in your app using SetProductData() function or set the absolute path of the file using SetProductFile() function.

The next thing you need to do is to set the product id of your application in your code using SetProductId() function. It sets the id of the product you will be adding licensing to.

SetProductData("PASTE_CONTENT_OF_PRODUCT.DAT_FILE");
SetProductId("PASTE_PRODUCT_ID", LA_USER);

If your app requires admin (root) privileges to run (e.g. services, daemons etc.), instead of passing LA_USER flag, you need to pass LA_SYSTEM flag.

In case your app doesn't have write access to the disk, you can use LA_IN_MEMORY flag instead, which causes all the data to be stored in the memory. But this would require you to activate the license every time you restart the app.

License activation

To activate the license in your app using the license key, you will use ActivateLicense() LexActivator API function. It invokes the /v3/activations Cryptlex Web API endpoint, verifies the encrypted and digitally signed response to validate the license.

int status;
status = SetProductData("PASTE_CONTENT_OF_PRODUCT.DAT_FILE");
if (LA_OK != status)
{
	// handle error
}
status = SetProductId("PASTE_PRODUCT_ID", LA_USER);
if (LA_OK != status)
{
	// handle error
}
status = SetLicenseKey("PASTE_LICENCE_KEY");
if (LA_OK != status)
{
	 // handle error
}
status = SetActivationMetadata("key1", "value1");
if (LA_OK != status)
{
	 // handle error
}
status = ActivateLicense();
if (LA_OK == status || LA_EXPIRED == status || LA_SUSPENDED == status)
{
	printf("License activated successfully: %d", status);
}
else
{
	printf("License activation failed: %d", status);
}

The above code should be executed at the time of license activation, ideally on a button click.

Verifying license activation

Each time, your app starts, you need to verify whether your license is already activated or not. This verification should occur locally by verifying the cryptographic digital signature of activation. Ideally, it should also asynchronously contact Cryptlex servers to validate and sync the license activation periodically. For this, you need to use IsLicenseGenuine() LexActivator API function.

int status;
status = SetProductData("PASTE_CONTENT_OF_PRODUCT.DAT_FILE");
if (LA_OK != status)
{
	// handle error
}
status = SetProductId("PASTE_PRODUCT_ID", LA_USER);
if (LA_OK != status)
{
	// handle error
}
status = IsLicenseGenuine();
if (LA_OK == status || LA_EXPIRED == status || LA_SUSPENDED == status  || LA_GRACE_PERIOD_OVER == status)
{
	printf("License is genuinely activated: %d", status);
}
else
{
	printf("License is not activated: %d", status);
}

The above code should be executed every time user starts the app. After verifying locally, it schedules a periodic server check in a separate thread.

Need more help

In case you need more help with adding LexActivator to your app, we'll be glad to help you make the integration. You can either post your questions on our support forum or can contact us through email.