Blog on Software Licensing, Commercialization, and Revenue Optimization

New Client API for C++

We have now finalized the last bits that were left to make the C++ client API more reliable and easier to integrate. This is great news if you develop applications in C++ (for instance, drivers, connected products as a service, IoT products, and more).

Right now, it offers the activation method, which is the method that should always be called to either verify or activate a license. If there are other methods that you would find useful, please get in touch with us.

The project has been lead by Martin Svedin, Lead Developer.

On the technical side

Our client API in C++ is quite different from its .NET counterpart. The main difference is in error handling, the protocol under the hood and the ability to perform API requests outside of our API (which uses curl by default). Extensions functions (ability to chain together several constraints together) in the C++ client are similar to the .NET client.

How to perform activation

In the .NET client, the only object you need is LicenseKey. In the C++ client, there is a similar class called LicenseKey (which contains license key parameters such as features). However, in order to retrieve a LicenseKey object, you cannot just call the activation method. Instead, you need to use an intermediate class called RawLicenseKey. That is, when you call the activation function, it will return a RawLicenseKey, which can be used to create a LicenseKey object.

The only difference between RawLicenseKey and LicenseKey is that the former one contains signature whereas the latter one does not. If you want to support offline activation, you should save RawLicenseKey object (the license and the signature, as described here). However, when you verify the license parameters, LicenseKey should be used instead.

Adding constraints

Adding a chain of constraints on LicenseKey object is very similar to the way it is done in .NET. For example, in .NET, to check that feature 1 is enabled and the key has not expired, you would type:

licenseKey.HasNotExpired().HasFeature(1).IsValid() // returns true if the constraints are satisfied

In the C++ client, it’s quite similar:

license_key->check()->has_not_expired(123456789)->has_feature(1) // returns true if the constraints are satisfied

A minor difference is that has_not_expired requires the current time as a Unix time stamp in seconds.

Public Key extraction

Another point worth mentioning is how you insert your public key (not the access token) into the C++ client. You can find your RSA public key here that has a structure similar to the one below:


When you specify the modulus and exponent, you can just copy them directly from your public key as shown below:

skm_handle.signature_verifier.set_modulus_base64(e, "sGbvxwdlDbqFXOMlVUnAFgteQ==");
skm_handle.signature_verifier.set_exponent_base64(e, "AQAB");

This has to be done before any activation request is sent, as shown here.


This was a short summary of the C++ client, with focus on users that are familiar with our .NET client. For further information, please see the GitHub repository and API documentation Please get in touch with us should you have any questions! One more thing, please review the third party licenses when you are ready to release your application.

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We’ve updated the license agreement to comply with GDPR

This week we’ve updated our terms of use, which now includes a new separate document (named Agreement) that clarifies the way your data is processed. In addition, we have also changed the party that provides the service, which is now Cryptolens AB. General Data Protection Regulation (GDPR) will be enforceable May 25th, 2018.

Important Considerations

When your customers are running your application, personal information such as the IP address is sent to Cryptolens AB. GDPR aims to protect users’ privacy, which means that it is important that you have a consent from your customers in doing so.

To make sure that you are compliant, our lawyer has composed an excerpt that you can insert into your agreement.

Binding the agreement to your customers

If you are targeting a large number customers, it may not be feasible to get a signed copy of the agreement. Instead, there are several ways you can make it binding online. We have listed several suggestions below:

  1. Before your customers can use your application, they should have opened a window that shows the Terms of the agreement (if you have your own end user license agreement) together with the Consent to personal data processing.
  2. It must be ensured that your customers have read the documents before they can use your application. There are different ways to do this and a function with a non-pre-filled box can be used. The customer must actively tick the box to approve the Terms of the agreement and the Consent to personal data processing.

If you would have any questions, please feel free to contact us.

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Updating pricing for better accessibility

Several days ago, we updated our pricing page with the aim of making SKM more customized to your business needs. Before, we had three types of subscriptions, but we quickly realized that all our customers had different requirements of the set of tools they need (eg. licensing, payments and analytics). Therefore, we want to focus on giving you the tools that better satisfy your requirements.

This means that we will use a usage based licensing model where you only pay for the modules you use and their usage. However, we also plan to introduce a standard pricing tier that can be used by those without specific requirements. This is coming soon, already in the beginning of next month. Using this approach, we hope that we can help both early stage startups as well as larger enterprises with custom needs.

In general, this change will increase the price of our core licensing offering. This only affects customers that registered a subscription in 2017 (i.e. those of you who had a subscription before 2017 will not be affected). We understand that this can have an impact on your plans, which is why we have developed a general procedure of how this change is implemented:

  • If your subscription is about to expire (or has expired), you will get up to 3 months for the same price as before.
  • Within those 3 months, we will give you an offer based on your needs.
  • In specific cases, we are ready to adjust the rules above (eg. generally for start ups and/or students).

The reason behind the changes is because SKM has evolved from being a hobby-project into a real company. This means that we can invest into better infrastructure, focus on upgrades and new features, and be able to provide a system that is compliant with various types regulations (for example, we are already GDPR compliant).

But most importantly, our goal is to ensure that you can focus on the core features of your application, and not have to think about licensing and payments.

For example, we have recently released support for platforms using C++, new Web API methods and many other updates. In the coming week, we will release even more visible changes, such as the “User Login Authentication” project, which is a new and more secure way of licensing applications. Please keep visiting our blog for more information.

To sum up, we do everything we can to stay innovative and provide you with a modern licensing system that you can rely on.


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New version of SKM Client API, 4.0.2

Today we’ve released a new major version of SKM Client API for .NET. The important takeaway from our release notes is that we have have fixed the networking issue with applications running in a corporate environment (eg. VPN) and those running through a proxy. This is good for those of you that develop enterprise applications. Moreover, we’ve brought support for SHA-256, which is now the default hash function for machine codes.

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Secure your account using 2-step verification

Now you can secure your account even further using two-factor authentication (2FA). In addition to your password, you will have to enter a short 6-digit code each time you log in, which helps to keep your account protected.

Enable 2-step verification

You can access this page directly here.

  1. Go to the Account Settings page
  2. Click on “Configure 2-step verification”
  3. Check “Enable Two Step Authentication” checkbox
  4. Scan the QR code with Google Authenticator (note: there are other alternatives such as Authy if you already have oen of them installed). If you want to get Google Authenticator, you can get it for

Open Source

At SKM, open-mindedness and transparency are at the core of everything we are doing. Therefore, we’ve open-sourced the core parts of 2-step verification, freely available on GitHub. You can learn more about our other open-source projects at

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Adding Enterprise Licensing and Enterprise-Grade Support

SKM platform is being relied upon by many software developers and vendors of various sizes. Today, we are happy to introduce SKM Enterprise, a tailored solution for high volumes of end customers, with custom development of functionalities to support all types of software and workflows (from mission critical applications to large scale usage). In addition, we are now offerring extended support (eg. phone and email support) aimed at enterprise customers.

Our aim is to make it easy for software developers and vendors to focus on developing functionalities that really matter to their customers and that make them a world leader in their area.

By making software licensing simple and affordable, we hope that more companies will be more productive and profitable, and in this way make their product more innovative and beneficial to their customers.

Getting in touch

If you want to get in touch, please send us an email at support (at) or visit our office at Lindstedsvägen 24, Stockholm (4th floor). We look forward to meeting you!

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How to Skip Royalties for Mobile Apps using Software Licensing

Problems with App store?

Limited Functionality

One clear problem with any App store is that you’re locked in to use their limited set of licensing models (i.e. ways to sell your app). This is evident when you want to support proper subscription based model (i.e. customers need to pay on a monthly or early basis to continue to use your app). Many big companies, such as Microsoft and Adobe, are starting to charge their customers on a recurring basis, for instance in Office 365 and Adobe Creative Cloud. Now, you no longer buy the “product” but rather the “service”, which means that we want to give our customers a great user experience independent of the platform, may it be a tablet, a smartphone or a PC. Unfortunately, this is very difficult to implement and manage across multiple platforms  if you use built in functionality of the App store (and other app stores) because you’re locked in into their ecosystem.

High Royalties

Not only are you locked in into their ecosystem, they also take 30% of your revenue that you could have used to develop your application further.

Say you sell your service for $100/per month. Then you have to pay $30 per month in royalties, which adds up to almost $400 per year. Note, this is in addition to the fee that you payed to register a developer account.

How is this solved now?

One question that comes into our mind is following: How do companies like Spotify and Uber avoid to pay Apple the 30% transaction fee? The common denominator is that they use a custom licensing component that they maintain themselves. For example, to use Spotify, you need an active subscription (even if the app is free), which you can get outside of the Apple store, for example, on Spotify’s website. So, technically, no transaction occurred in the app itself.


The idea is to avoid using the built-in functionality of the App store as much as possible. You can do this in the following two ways: either you develop a licensing component from scratch or use a third party.

Building from Scratch

If you have some time at your disposal, you can create a licensing system from scratch or use an open source library, such as SKGL. The advantage is that you get to design it specifically for your needs. Using open-source systems can save you some time, but please keep in mind that you might instead need to spend time on configuring it and possibly extending depending on your requirements.

Using Third Party

The idea here is simple: “Why invent the wheel?”. Software licensing and monetization is such a common problem so there are solutions out there that can do just that.

First of all, they will probably cover many cases and secondly they are also cheaper than doing it on your own (after all, think about the time it would take, which is approx. 2-3 months, and later maintenance).

The critical bit is maintenance. Imagine that your business model changes and you have to restructure your licensing solution. If you use a third party, they most likely have what you’re looking for, so changing won’t be hard. Otherwise, you have to do it yourself from scratch.

Example solution using SKM

In order to get a working licensing component, one way to go is to use SKM – a cloud based licensing as a service. SKM is like a toolbox that contains many of the tools that you would need to set up a licensing system within hours. In comparison to many of the alternative solutions, it’s aim is to be accessible, which includes being affordable and simple-to-use. Moreover, one of the values is transparency and developer friendliness; many of the tools used in SKM are available open source and free of charge.  It’s very simple to get started.

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Happy New Year (2017)

This year has almost reached its end (at least here in Sweden) and within several hours a new year will begin – 2017.

By looking back on 2016, I’m very happy that we are getting closer to achieve our mission: to make software licensing more accessible. This is thanks to our partners and customers, who continue to support us with new ideas and insights. I’m very thankful to all of you.

Soon 2017 will begin, and I’m convinced that this new year will come with new interesting challenges and opportunities for all of us.

I wish you all the very best! 🙂


Lead Developer, Founder

Fixed downtime Dec 18th due to invalid certificate

Today we had a major downtime because the new TLS certificate was not upgraded properly. This caused most of the versions of SKM Client API (aka SKGL Extension) not being able to validate license keys.

I’m very sorry for all the problems that this caused you. Downtimes occur because of various issues; at SKM we are constantly working on making sure to reduce them and their impact.

I’my happy to tell that this issue is now fixed!


Lead Developer

SKM’s Wiki Engine Open Source

The aim behind SKM is to make software licensing more accessible. By making it simple, it becomes more accessible.

This led to the construction of a new Wiki page, which you can find here:

The entire page is open source and does not require any server side (i.e. PHP/ASP.NET). You can find it here:

You can read more about open source at SKM:


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