Category: Tips on Using our Service

Protecting Rhinoceros plugins with software licensing

Rhinoceros® (aka Rhino 3D) is a powerful computer graphics and CAD application. It’s also quite extensible as it allows developers to create their own plug-ins and add-ons. The aim of this post is to give you quick way of getting started with software licensing in your application, with focus on .NET.

One way of developing Rhino 3D applications is using Visual Studio. To add a simple key verification mechanism, only three steps are necessary:

  1. Right click on your project in the Solution Explorer and click on Manage NuGet Packages.
  2. Search for Cryptolens.Licensing and install it.
  3. Add the code-snippet form this page in the code where the plugin loads for the first time.

You can know create a license key in the Cryptolens dashboard to test that the key verification code works. That should be it! If you would have any questions, please feel free to reach out.

License server for software licensing

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:

  1. Install the license server as described here.
  2. In the Key.Activate method, add LicenseServerUrl parameter and set it to point to the license server (the IP and port of are shown in step 1).

SendOwl and DPD integrations with Software Licensing

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.

Recurring Payments with Stripe combined with Software Licensing

A popular licensing model amongst software vendors is subscription-based licensing. It is generally seen as a smaller risk for the customer than traditional one-time payments (eg. which normally require a large commitment), but at the same time it provides recurring revenues for the software vendor.

You can get started with recurring payments by visit our help pages.


Recurring payments are implemented as a part of the customer portal. Thanks to this update, customers can not only manage their existing licenses but also subscribe for new ones.

Everything related to payments, plans and subscriptions is managed by Stripe, so if you’re already using Stripe, it’s quite easy to get started with the new recurring payments feature. If you do not have Stripe, it’s quite easy to get started. A tutorial can be found here.

In addition to recurring payments, the customer portal makes it possible to use user account authentication, described in the previous article.


Example when the customer has subscribed to a new plan:

The new license will show up on the home page of the customer:

Reviewing a license key and the subscription it is associated with:

Software licensing for PHP applications

We recently added support for key verification in PHP, available on GitHub. Below is the sample code that can be included into your application.


$activate = cryptolens_activate(
      // Access token
      // Product Id
    , 3646
      // License Key
      // Machine code
    , '289jf2afs3'

// $activate is now a boolean indicating if the activation attempt was successful or not


The repository contains all the necessary information to get the code to work (eg.. finding access tokens)

Usage-based (pay per use) software licensing in .NET

Many software vendors nowadays move away from one-time payments to other licensing models. One such example is the usage-based model. By doing so helps lowering the barrier of entry for new customers, as they no longer need to commit to the product long term, which is usually the case with one-time payments. If you already have a subscription model, supporting usage-based payments can help you to monetise a group of users who would otherwise not buy the product.

You can read the entire tutorial here.

Getting started

In Cryptolens, usage-based licensing can be implemented using data objects, aka custom variables. We can use these variables to record how often features are used and keep track of any usage credits that a customer has purchased. There are two ways of billing customers:

  • Upfront payment: customers need to purchase usage credits in advance.
  • Based on actual usage: customers pay for the actual usage in the end of the billing period.

Charging based on actual usage

If you choose to charge your customers based on actual usage, we can simply use the code below:

var auth = "Access token with AddDataObject, ListDataObject and IncrementIntValue permission. Please also set KeyLock value to '-1'";
var licenseKey = "LZKZU-MPJEW-TARNP-UHDBQ";

var result = Data.ListDataObjects(auth, new ListDataObjectsToKeyModel 
    Contains = "usagecount",
    Key = licenseKey,
    ProductId = 3349 

var obj = result.DataObjects.Get("usagecount");

if (obj == null)
    // make sure to create it in case it does not exist.
    Data.AddDataObject(auth, new AddDataObjectToKeyModel { Key = licenseKey, ProductId = 3349, Name = "usagecount", IntValue = 1 });

    if(res == null || res.Result == ResultType.Error)
        Console.WriteLine("Could not create new data object. Terminate." + res.Message);
    var res = obj.IncrementIntValue(auth, 1, licenseKey: new LicenseKey { Key = licenseKey, ProductId = 3349 });

    if (res == false) 
        Console.WriteLine("We could not update the data object. Terminate.");

Upfront payments

If you instead want to charge your users upfront, we need to create the data objects when creating the license. If you are using payment forms, we can set up two requests, one creating a new license and another creating a new data object (inspired by this tutorial), as the result from key creation will be “piped” into data object creation request. You can then have another payment form that allows users to refill their credits, in which case the custom field can be used.

You can use the code below to verify if the limit was reached inside your application:

var auth = "Access token with AddDataObject, ListDataObject and IncrementIntValue permission. Please also set KeyLock value to '-1'";
var licenseKey = "LZKZU-MPJEW-TARNP-UHDBQ";

var result = Data.ListDataObjects(auth, new ListDataObjectsToKeyModel { Contains = "usagecount", Key = licenseKey, ProductId = 3349 });
var obj = result.DataObjects.Get("usagecount");

var res = obj.DecrementIntValue(auth, decrementValue: 1, enableBound:true, lowerBound: 0, licenseKey: new LicenseKey { Key = licenseKey, ProductId = 3349 });

if (!res)
    Console.WriteLine("Could not decrement the data object. The limit was reached.");

Sending news and update notifications using Messaging API

The new Messaging API allows you to easily send notifications to some or all of your end users. For example, it can help you to notify customers running an older version of your application to upgrade as well as keep them updated about the latest news.

Getting Started

It’s quite simple to get started with the Messaging API. The dashboard is available here, which is where you can send the messages. In order receive them in your own app, you can use the GetMessages method. One thing to keep in mind are the two optional parameter, time and channel. These allow you to tell Cryptolens which messages you want to receive. Time is used as a reference when the last message was seen and channel is a way to group those messages. If these are not specified, all of the messages will be returned.

For example, let’s say you want to implement updates notifications. In that case, we can use the code below to ensure that only older versions of the software receive the message. The version itself is specified as a unix timestamp in the currentVersion parameter, which should be the time when you published the release.

var currentVersion = 1538610060;
var result = (GetMessagesResult)Message.GetMessages("token with GetMessages permission", new GetMessagesModel { Channel = "stable", Time = currentVersion } );

if(result == null || result.Result == ResultType.Error)
    // we could not check for updates
    Console.WriteLine("Sorry, we could not check for updates.");
else if (result.Messages.Count > 0)
    // there are some new messages, we pick the newest one 
    // (they are sorted in descending order)
    // No messages, so they have the latest version.
    Console.WriteLine("You have the latest version.");


You can see the entire tutorial about updates notifications for more details. There is also about notifications.

How to protect SDKs with Software Licensing in .NET

Software Development Kits (SDKs) are a great way to give your users the ability to build on top of the functionality offered by your library/package. From a licensing perspective, desktop apps and SDKs are quite similar, which we will go through in this article. We will first take a look at the applicable licensing models and then skim through some example code. You can jump directly to the tutorial here.

Licensing Models

SDK licensing is special since the developer of the SDK (the customer) is not its end user. Instead, it’s their customers that will be the end users. In this article we focus on “node-locked” and “pay per install” licensing models (you can read about all applicable licensing models here).

Node-locked is equivalent to “pay per machine”, which essentially means that each time a new machine activates the license, this is recorded so that it can be taken into account when you charge the developers (your customers). Each user will be able to re-install the app that uses the SDK any number of times, without affecting the counter.

Pay per install is similar to “pay per machine”, with the only difference being that fingerprints of the end user machines are not recorded. Instead, a counter is used that increment whenever the SDK is first launched. With this model you get a bit less control of end user instances, but since the fingerprints (aka machines codes) are not tracked, the subscription cost for Cryptolens will reduce significantly (since you are only paying per license key).

In both of the models above, you could create multiple plans for your customers that depend on the actual usage of the SDK. Eg. 1-10 could be a testing tier, 10-10,000 could be another pricing tier, and so on.


From a developer standpoint (eg. your customer), the license key will have to be specified to unlock functionality of your SDK. You could potentially have different pricing tiers depending on the methods that your customers will use. Below is an example of class initialisation that requires a license key to work.

var math = new MathMethods("FULXY-NADQW-ZAMPX-PQHUT");


To see all the code, please take a look at the entire tutorial.


If you have algorithms in your SDK that you want to be 100% secure from reverse-engineering, we would recommend to create an API endpoint for them hosted in the cloud. Most of the cloud providers support “server less” functions, eg Azure Functions and AWS Lambdas. These are quite simple to setup. Your server less functions would require a license key and potentially a machine code to return a successful response. On the client side, you could use libraries such as RestSharp to access your API endpoint. We will cover this in a future article.

New AI feature helps optimize software pricing

Setting the price for a product you intend to sell is hard, especially when pricing usually changes over time. Cryptolens’ new AI feature helps software providers set the price by analyzing how each individual user uses their software.

Problem with existing pricing models

It is often challenging for software providers to price their product optimally.

A good example that demonstrates this is when you set the price for accounting software. Imagine you have two groups of customers: those that use the software regularly in their profession (eg. accountants helping other companies) and those that only use it once a month (eg. small businesses). It makes sense to have different pricing models for these two groups: professionals can be charged monthly (and are very likely to pay more) and the smaller business can pay per usage (eg. per generated monthly report).

As a result, software providers are able to increase their revenues and capture both customer groups by taking into account the true value the software has for each group, and adjusting the pricing model to meet the needs for each group.

How Cryptolens’ new AI feature optimizes revenue

Cryptolens’ new AI feature analyzes the usage information generated by each user (and the history from previous users) and determines the value a product (and its features) has for each user, and then helps to determine the best pricing model for that particular user or user group.

For example, if the value of the features is higher than the price of the product, it would be reasonable to increase the price. If, however, only a subset of the product’s features are used, a new product based on a subset of the features offered at a lower price could be a solution (or potentially suggest an alternative licensing model such as usage-based model).

The goal is to provide insights on the value of a product and its features for each user, and assist in creating new product offerings with more optimal pricing.

Getting started

In order to benefit from our AI analysis, the following is required:

First, you need to register each time a customer interacts with a certain feature of the product (if you have a licenseKey object, you can call the new RegisterEvent method). For example, when they start the salary module (if it’s an accounting software), you can send FeatureName=”SalaryModule” and EventName=”start”. If they generate a report, you can keep the feature name, but change the event name to “report_generated”.

The second step is to register successful transactions (eg. when the customer buys the software). In that case, you can still call RegisterEvent method, and include the value and currency parameters.

Please get in touch with us if you need any help setting this up. We are currently looking for beta testers and would be happy if you can participate. You can reach out to us at

Once enough data is collected, you will be able to see it in the analytics dashboard.