Trialware/licensing strategies

Question

I wrote a utility for photographers that I plan to sell online pretty cheap ($10). I'd like to allow the user to try the software out for a week or so before asking for a license. Since this is a personal project and the software is not very expensive, I don't think that purchasing the services of professional licensing providers would be worth it and I'm rolling my own.

Currently, the application checks for a registry key that contains an encrypted string that either specifies when the trial expires or that they have a valid license. If the key is not present, a trial period key is created.

So all you would need to do to get another week for free is delete the registry key. I don't think many users would do that, especially when the app is only $10, but I'm curious if there's a better way to do this that is not onerous to the legitimate user. I write web apps normally and haven't dealt with this stuff before.

The app is in .NET 2.0, if that matters.

Answer 1

In these sort of circumstances, I don't really think it matters what you do. If you have some kind of protection it will stop 90% of your users. The other 10% - if they don't want to pay for your software they'll pretty much find a way around protection no matter what you do.

If you want something a little less obvious you can put a file in System32 that sounds like a system file that the application checks the existence of on launch. That can be a little harder to track down.

Answer 2

There's not much point to doing complicated protection schemes. Basically one of two things will happen:

1. Your app is not popular enough, and nobody cracks it.

2. Your app becomes popular, someone cracks it and releases it, then anybody with zero knowledge can simply download that crack if they want to cheat you.

In the case of #1, it's not worth putting a lot of effort into the scheme, because you might make one or two extra people buy your app. In the case of #2, it's not worth putting a lot of effort because someone will crack it anyway, and the effort will be wasted.

Basically my suggestion is just do something simple, like you already are, and that's just as effective. People who don't want to cheat / steal from you will pay up, people who want to cheat you will do it regardless.

Answer 3

If you are hosting your homepage on a server that you control, you could have the downloadable trial-version of your software automatically compile to a new binary every night. This compile will replace a hardcoded datetime-value in your program for when the software expires. That way the only way to "cheat" is to change the date on your computer, and most people wont do that because of the problems that will create.

Answer 4

If you are planning to continue developing your software, you might consider the ransom model:

http://en.wikipedia.org/wiki/Street_Performer_Protocol

Essentially, you develop improvements to the software, and then ask for a certain amount of donations before you release them (without any DRM).

Answer 5

One way to do it that's easy for the user but not for you is to hard-code the expiry date and make new versions of the installer every now and then... :)

If I were you though, I wouldn't make it any more advanced than what you're already doing. Like you say it's only $10, and if someone really wants to crack your system they will do it no matter how complicated you make it.

You could do a slightly more advanced version of your scheme by requiring a net connection and letting a server generate the trial key. If you do something along the lines of sign(hash(unique_computer_id+when_to_expire)) and let the app check with a public key that your server has signed the expiry date it should require a "real" hack to bypass.

This way you can store the unique id's serverside and refuse to generate a expiry date more than once or twice. Not sure what to use as the unique id, but there should be some way to get something useful from Windows.

Answer 6

Try the Shareware Starter Kit. It was developed my Microsoft and may have some other features you want.

http://msdn.microsoft.com/en-us/vs2005/aa718342.aspx

Answer 7

I am facing the very same problem with an application I'm selling for a very low price as well.

Besides obfuscating the app, I came up with a system that uses two keys in the registry, one of which is used to determine that time of installation, the other one the actual license key. The keys are named obscurely and a missing key indicates tampering with the installation.

Of course deleting both keys and reinstalling the application will start the evaluation time again.

I figured it doesn't matter anyway, as someone who wants to crack the app will succeed in doing so, or find a crack by someone who succeeded in doing so.

So in the end I'm only achieving the goal of making it not TOO easy to crack the application, and this is what, I guess, will stop 80-90% of the customers from doing so. And afterall: as the application is sold for a very low price, there's no justification for me to invest any more time into this issue than I already have.

Answer 8

EDIT: You can make your current licensing scheme considerable more difficult to crack by storing the registry information in the Local Security Authority (LSA). Most users will not be able to remove your key information from there. A search for LSA on MSDN should give you the information you need.

Opinions on licensing schemes vary with each individual, more among developers than specific user groups (such as photographers). You should take a deep breath and try to see what your target user would accept, given the business need your application will solve.

This is my personal opinion on the subject. There will be vocal individuals that disagree.

The answer to this depends greatly on how you expect your application to be used. If you expect the application to be used several times every day, you will benefit the most from a very long trial period (several month), to create a lock-in situation. For this to work you will have to have a grace period where the software alerts the user that payment will be needed soon. Before the grace period you will have greater success if the software is silent about the trial period.

Wether or not you choose to believe in this quite bold statement is of course entirely up to you. But if you do, you should realize that the less often your application will be used, the shorter the trial period should be. It is also very important that payment is very quick and easy for the user (as little data entry and as few clicks as possible).

If you are very uncertain about the usage of the application, you should choose a very short trial period. You will, in my experience, achieve better results if the application is silent about the fact that it is in trial period in this case.

Though effective for licensing purposes, "Call home" features is regarded as a privacy threat by many people. Personally I disagree with the notion that this is any way bad for a customer that is willing to pay for the software he/she is using. Therefore I suggest implementing a licensing scheme where the application checks the license status (trial, paid) on a regular basis, and helps the user pay for the software when it's time. This might be overkill for a small utility application, though.

For very small, or even simple, utility applications, I argue that upfront payment without trial period is the most effective.

Regarding the security of the solution, you have to make it proportional to the development effort. In my line of work, security is very critical because there are partners and dealers involved, and because the investment made in development is very high. For a small utility application, it makes more sense to price it right and rely on the honest users that will pay for the software that address their business needs.

Answer 9

just be cool about the license. explain up front that this is your passion and a child of your labor. give people a chance to do the right thing. if someone wants to pirate it, it will happen eventually. i still remember my despair seeing my books on bittorrent, but its something you have to just deal with. Don't cave to casual piracy (what you're doing now sounds great) but don't cripple the thing beyond that. I still believe that there are enough honest people out there to make a for-profit coding endeavor worth while.

Answer 10

Don't have the evaluation based on "days since install", instead do number of days used, or number of times run or something similar. People tend to download shareware, run it once or twice, and then forget it for a few weeks until they need it again. By then, the trial may have expired and so they've only had a few tries to get hooked on using your app, even though they've had it installed for a while. Number of activation/days instead lets them get into a habit of using your app for a task, and also makes a stronger sell (i.e. you've used this app 30 times...).

Even better, limiting the features works better than timing out. For example, perhaps your photography app could limit the user to 1 megapixel images, but let them use it for as long as they want.

Also, consider pricing your app at $20 (or $19.95). Unless there's already a micropayment setup in place (like iPhone store or XBoxLive or something) people tend to have an aversion to buying things online below a certain price point (which is around $20 depending on the type of app), and people assume subconciously if something is inexpensive, it must not be very good. You can actually raise your conversion rate with a higher price (up to a point of course).