Unity is a powerful cross-platform game engine. Since it uses C# as the scripting language, we can easily integrate it with Cryptolens client library. In this post, we explain how you can add license key verification into a Unity game and briefly cover payment integration.
Adding software licensing
Download the binaries (please pick those without “System.Management”).
Once licensing is in place, the next step is to add payment integration. Since Cryptolens is cloud-based, you can easily integrate it with your own billing system or use our existing integrations with popular platforms such as Stripe and PayPal. You can read more about how this can be accomplished here.
Please feel free to reach out should you have any questions!
Many times your customers may have either restricted internet access or no internet access at all. Although Cryptolens is a cloud-based licensing solution, you can still use it to protect offline devices. In this post, we cover three ways internet access can be restricted and how license key verification can be performed.
Periodic internet access
If your users are connected to the internet on a regular basis, we can cache the response from the “Activate” method each time we are able to contact the server. If, at some point, internet connection would not be present, we would fallback on a cached version of the license object.
When using this approach, it’s important to define how long time your users can be offline. There is a field called “SignDate” in the license key object, which is the time when the response was signed by the server (i.e. the last time you successfully called Activate). So, if you only want to allow your users to be offline for 30 days, you can compare the current date with the “SignDate”.
License server (re-routing)
If your users have certain devices that have no direct internet access, one option is to use a license server, which will re-route all requests through a server hosted by the user. Only the server has internet access.
There is currently a Windows version of the server, freely available on GitHub.
Air gap (no internet)
If the devices have no internet access at all, we can use a similar idea that was described in periodic internet access, with the only difference that we always fallback on the license file.
In Cryptolens, there are three ways you can create such a file:
In the dashboard
Next to each license key, there is a yellow button which can be used to create license files:
Using activation forms
Activation forms allow your customers to download activation files themselves.
Using the API
If you want to automate license file creation, you can either call the Activate method using one of our client APIs or call the Web API directly (eg. using curl).
Floating licenses makes it easier for your customers to switch between machines that actively run your software, without having to deactivate them first. For instance, you can constrain the number of concurrent users to 10, but still allow the software to be installed on eg. 100 computers.
In Cryptolens, floating licensing works by letting your app to regularly poll the server to check if the number of concurrent users has been exceeded, which can be accomplished with the code snippet below:
import io.cryptolens.methods.*;
import io.cryptolens.models.*;
public static void main(String args[]) {
String RSAPubKey = "RSA Public Key";
String auth = "Access token";
LicenseKey license = Key.Activate(auth, RSAPubKey, new ActivateModel(3349, "MTMPW-VZERP-JZVNZ-SCPZM", Helpers.GetMachineCode(), 300, 1));
if (license == null || !Helpers.IsOnRightMachine(license, true, true)) {
System.out.println("The license does not work.");
} else {
System.out.println("The license is valid!");
System.out.println("It will expire: " + license.Expires);
}
}
Normally, if the app stops polling the server, that user will be automatically deactivated within the specified period of time. However, if you want to deactivate it instantly, you can use the code below:
import io.cryptolens.methods.*;
import io.cryptolens.models.*;
public static void main(String args[]) {
String auth = "";
boolean result = Key.Deactivate(auth, new DeactivateModel(3349, "MTMPW-VZERP-JZVNZ-SCPZM", Helpers.GetMachineCode(), true));
if (result == true) {
System.out.println("Deactivation successful.");
} else {
System.out.println("Deactivation failed.");
}
}
Today, we have released an update to the Java client API that allows you to easily verify license keys. You can read more about how to add it to your project in the GitHub repo. Below is an example of the code that you can use in your application.
import io.cryptolens.Cryptolens;
import io.cryptolens.Helpers;
import io.cryptolens.LicenseKey;
public class Main {
public static void main(String[] args) {
String RSAPubKey = "<RSAKeyValue><Modulus>sGbvxwdlDbqFXOMlVUnAF5ew0t0WpPW7rFpI5jHQOFkht/326dvh7t74RYeMpjy357NljouhpTLA3a6idnn4j6c3jmPWBkjZndGsPL4Bqm+fwE48nKpGPjkj4q/yzT4tHXBTyvaBjA8bVoCTnu+LiC4XEaLZRThGzIn5KQXKCigg6tQRy0GXE13XYFVz/x1mjFbT9/7dS8p85n8BuwlY5JvuBIQkKhuCNFfrUxBWyu87CFnXWjIupCD2VO/GbxaCvzrRjLZjAngLCMtZbYBALksqGPgTUN7ZM24XbPWyLtKPaXF2i4XRR9u6eTj5BfnLbKAU5PIVfjIS+vNYYogteQ==</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>";
Cryptolens cryptolens = Cryptolens.getDefault();
cryptolens.setRSAPublicKey(RSAPubKey);
Cryptolens.ActivateResponse response =
cryptolens.activate( "WyIyNTk1IiwidVVrQm94OGlYS3pHZlhTc0x6Rm9mN1piektrT0FSd0REaFZ0ZXZJMSJd"
, 3349
, "ICVLD-VVSZR-ZTICT-YKGXL"
, Helpers.GetMachineCode()
);
if (!response.successful()) {
System.out.println("Failed to activate!");
Cryptolens.ActivateServerError er = response.getServerError();
Exception ex = response.getException();
if (er != null) {
System.out.println("Server error: " + er);
}
if (ex != null) {
ex.printStackTrace(System.out);
}
return;
}
LicenseKey licenseKey = response.getLicenseKey();
System.out.println("Activation was successful!");
System.out.println(licenseKey.getKey());
System.out.println(licenseKey.getF1());
}
}
Update 2019-12-04: We have updated the Python library so that it’s easier to obfuscate. Please check out the latest article with tips on monetizing Python applications (it covers code obfuscation, license verification and accepting payments).
Today, we released a library for license key verification in Python, freely available on GitHub. The code below checks license validity with the server (performing all the necessary cryptographic checks under the hood). Please run “pip install licensing” before running the code below.
from licensing.helpers import Helpers
from licensing.models import Response, RSAPublicKey
from licensing.methods import Key
pubKey = "<RSAKeyValue><Modulus>sGbvxwdlDbqFXOMlVUnAF5ew0t0WpPW7rFpI5jHQOFkht/326dvh7t74RYeMpjy357NljouhpTLA3a6idnn4j6c3jmPWBkjZndGsPL4Bqm+fwE48nKpGPjkj4q/yzT4tHXBTyvaBjA8bVoCTnu+LiC4XEaLZRThGzIn5KQXKCigg6tQRy0GXE13XYFVz/x1mjFbT9/7dS8p85n8BuwlY5JvuBIQkKhuCNFfrUxBWyu87CFnXWjIupCD2VO/GbxaCvzrRjLZjAngLCMtZbYBALksqGPgTUN7ZM24XbPWyLtKPaXF2i4XRR9u6eTj5BfnLbKAU5PIVfjIS+vNYYogteQ==</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>"
res = Key.activate(token="WyIyNTU1IiwiRjdZZTB4RmtuTVcrQlNqcSszbmFMMHB3aWFJTlBsWW1Mbm9raVFyRyJd",\
rsa_pub_key=pubKey,\
product_id=3349, key="ICVLD-VVSZR-ZTICT-YKGXL", machine_code="test")
if res[0] == None:
print("An error occured: {0}".format(res[1]))
else:
print("Success")
You can find more information the parameters, etc here.
AutoCAD® is a powerful computer-aided design (CAD) software. It’s also quite extensible since anyone can easily create plug-ins. In this post, we briefly summarise several tips on how to securely license and sell your AutoCAD plug-ins.
Creating the plugin
If you are about to create a new AutoCAD plug-in, we would recommend to review the following tutorial provided by Autodesk.
Adding software licensing
Assuming you have Visual Studio 2017 open, you can add a simple key verification mechanism as described below:
Right click on your project in the Solution Explorer and click on Manage NuGet Packages.
Add the code-snippet form this page in the code where the plugin loads for the first time.
Selling the plug-in
One way to sell AutoCAD plug-ins is by publishing them in the Autodesk App Store, where a basic licensing mechanism is already provided. The problem with this approach is that the licensing models available are quite limited (eg. you can only charge your customers once for the plug-in and they will be able to use it in perpetuity). For instance, selling your plug-in as a service (subscription model) is not supported.
A better approach is to still publish your plug-in in the Autodesk App Store and set it to be a free app. You can then ask your customers to get a separate license key to be able to unlock all features.
You can read more about various ways of selling your software in our help pages. I would also recommend to check out the available licensing models.
If you have any questions, please feel free to reach out!
One of the problems experienced by software vendors when selling to large customers is that some of their machines that will be running the software do not have direct internet access.
Although it is still possible to use offline activation, having an active connection to Cryptolens makes things much easier for both you as the software vendor and your customers.
To solve this, we can use a license server that will re-route all the license verification requests from the computers in the network to Cryptolens, as shown below:
If you have already implemented key verification in your application, the license server can be set up quite quickly in two steps:
On a mission to make software licensing more accessible, we have recently improved our Web API to make integrations with other services easier. For example, we have made it possible to return license keys as plain text, which many third party platforms require.
When selling software, there are two problems that need to be solved: payment processing and software licensing. Cryptolens core has always been the comprehensive licensing API. If you are using SendOwl or DPD, you can keep using them for payments and Cryptolens for software licensing.
If you have a new project, I would recommend to check out our new tutorial about built-in recurring payments and payment forms.
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