Implementing Licencing mechanism for a Software [closed] - algorithm

Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 7 years ago.
Improve this question
I am thinking of implementing a good licensing mechanism that has a good resistance against piracy. The required mechanism should not use an internet connection at each and every time the software is used. I am thinking of a mechanism based on hardware IDs etc. Do you guys have any better suggestions? What are the parameters/algorithms/characteristics that I need to concern to make a hack proof license mechanism?

Ideally you need something that is OS independent.
I would recommend that you embed the license protection within your code or wrap your application within it in such a way that it cannot be run without the copy protection code having run first.
It would be best if your application needs a license key file in order to operate and that this isn't generated locally.
One way of doing this is that your application generates some form of image code based upon the hardware on it's initial run. This is supplied to you and in return you supply the license key which will allow the code to run. Best to base the hardware image around CPU and motherboard as these will change the least often.
Your app. should check against hardware image and license key whenever it is run.
If you want your app. license time limited then it should also keep track of how long it has run and embed it within the license key file.
Don't forget to encrypt the license file.
Also don't forget to make it more difficult to reverse compile your executable by use of a dotfuscator or similar.

Check this question: What copy protection technique do you use?
It also links to other related questions.

First of all, nothing is hackproof, so i wouldn't spend too much time on protecting your software.
The downside of a mechanism based on hardware IDs is when a user buys a new computer or upgrades most of his computer he needs to update the key too.
HWHash is a pretty good HardwareID implementation, but i guess there are more (free) solutions.
At work we use Hardlock and Hasp keys, but these are usbkey solutions which are not very efficient for small applications.

I am thinking of implementing a good licensing mechanism that has a good resistance against piracy. The required mechanism should not use an internet connection at each and every time the software is used.
Then how about a periodic online check of the licence?
When the user logs in the first time, the user verifies the install against his account and a licence file is stored on the users PC. This licence file is encrypted and contains all the data needed to uniquely identify the license. This is all stored on your server.
The licence file expires in set number of days or even months. Logging in after the file expires checks against the account and verifies its legitimacy. You might even consider generating a new licence file at this time.
There should be some smarts that give some leeway in the case that the users internet is down and the licence cannot be registered. Perhaps 7 days.
If the software is reinstalled on a new computer the user has to repeat the verification process.
As the others have stated there is no way to beat a determined pirate, since such a person will hack the code, but this should prevent or slow down casual piracy.

You can check out Microsoft's SLP - I haven't used it, but it definitely looks interesting (yknow, IF you're into MS stuff...)
One important point to note - no licensing mechanism will protect you from piracy, or even substantially reduce it. By definition, the licensing mechanism will be client-side - which is inherently breakable. Take a look at all what happened with DRM...
Your guideline should therefore be usability - the intent should be to use it as a general policy, the good guys will be comfortably limited to what they're supposed to be allowed to do, and the bad guys - well, the bad guys will get around your intent anyway, your best hope is to make it more work.

I'd be very wary of published software protection mechanisms, as they are much more likely to have published hacks. You are probably better off using some of the techniques to get a unique persistent ID and use this to roll your own protection mechanism. I also think that it is a poor idea to simple check the license whenever you run the program, as this leads the hacker to the location of your proection mechanism. IMO, your are better checking the license in a more random fashion, and more than once per session.
FWIW, I use hardware locks (hasp) for my high end desktop software, and device ID based licensing on mobile solutions. If you are selling small quantities of high cost software in a vertical market, IMHO, a good license protection mechanism makes sense, and hardware dongles work well. My experience has been that people will use more licenses than they purchase if this is not in place. For high volume, low cost software, I'd tend to live with the piracy based on increasing the size of the user base and product visibility.

Related

Algorithm for activation key- Security

I'm writing a software application that the user needs to buy a license for and activate it. I need suggestions on how to start about writing a powerful algorithm for code generation and of course, code checking. I know that people can reverse engineer the code and make a keygen, however, my question is two parts:
In general, regardless of the application being cracked this way, how can I start writing an algorithm to accept a certain Serial or String or a combination. (e.g is that the right thing? e.g: the first number is from 3-9 the second should be the first - 3, while the third number should be the second * + ....whatever...??)
What is the best approach for protecting a Desktop application from piracy without dealing with the internet. Is it the algorithm (make it harder to reverse engineer), protect the source code from being seen after application is installed somewhere?? ...??
PS: Maybe it is worth to mention that I am using Java as my development language.
Thanks
It sounds like you might benefit from the public-key cryptography approach.
This can be broken down into two sub points:
A. Have you read this thread here on SO? It might give you some breadth on the issue.
B. As #Jaka said, it's not a great challenge (from what I've read) to produce human readable code from Java byte code. You can run your code through an obfuscator to make it more difficult for someone to produce human readable code from it, but if someone really wants to read your code, they'll almost always find a way. The best approach to combat this is to take the advice in the SO thread I linked to: make it easier for someone to buy your app than for someone to steal it.
(edited after stated he's using Java)
For the license keys you could use an encryption with public-private keys. In this way you could either embed the private key into the software and encrypt a string which would mean something to your software (like which features of your software are licensed). Or you could embed the public and give the software a string with special meaning and sign it with your private key. The software could then check if the signature is valid.
edit: labratmatt was faster with the public-private key answer :)
Obviously second part of your protection would need to deal with making your software hard to disassemble and debug (this is how crackers examine your software and try to bypass the protection with a patch or they try to figure out how they can make a keygen). This part is actually much harder and involves techniques like encryption the whole executable and wrap it inside a loader which decrypts it at runtime. The loader can also use various techniques to detect the presence of debuggers.
edit: Since you mentioned that the application is written in JAVA, then this encrypting and packing step is even more important as JAVA can easily be decompiled into a very human readable form. There are "obfuscator" programs which mess around with the classes so that the decompilers can't generate readable code, but cracking this is still much easier than cracking something compiled to machine code.
If you don't want to spend time with developing your own protection you can also use one of commercial protection software. There are quite a lot of them to choose from and they offer numerous protection schemes (dongles, time based licenses,...)
Lots of commercial software uses packages like FlexNet, HASP, Wibu-key
Suggestion: encrypt the part of the application that provides licensed-only functionality. The user needs a key you provide on purchase in order to use that portion of the code.
If you ever let the user run the code you want to protect before they've purchased, there is no significantly secure offline solution. At best, you can stop the most casual piracy.
You should also thing about doing it in a way that one key cannot be used on two different computers. Just to prevent a company buying one key and using it for many instalations.
Did you write your own JRE too? Building a secure, capable activation system that deals smoothly with the range of user scenarios you'll encounter (people with no network connection, a firewall, a proxy server etc) and has been thoroughly tested in the field takes considerable domain expertise and time.
As a supplier of such systems we do have as self-interest to declare, but we also have data - we see many companies who put their trust in a developer who says they can put together a licensing system, then later they come back to us as it never did what they needed. This article (of mine) expands on the issues: http://knol.google.com/k/dominic-haigh/issues-to-consider-before-building-your/2zijsseqiutxo/6#
https://superuser.com/questions/14224/how-to-explain-drm-cannot-work/14254#14254
Even if you did put a very powerful lock on your software, pirates would still find a way to crack it and put it on a torrent site. (case in point: Spore)
You are talking about DRM, and there's no easy way (if any) to lock pirates out of pirating your software. And besides, you are competing with free products that can do what your software does (always the case), so you should focus more on making your software easy to install and use, not hard to install and use for more than you intended.

How to deploy a commercial portable application? [closed]

Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 7 years ago.
Improve this question
We plan to sell a Windows portable application. By 'portable' I mean that it can be run from any Windows computer without installing it. For example from an USB stick etc. However the application while (theoretically) it can work anywhere, is targeted to LAN environments.
What solutions do you see that while keeping this advantage (in a more or a lesser degree) to still make money from it?
PS: The application is/will be written in Delphi.
If you are offering your product for sale and not for free, then you will most likely make money from it. If what you are asking is how to maximize the income and prevent piracy, then that is a more specific question.
The key to making money with software is to make the purchase route less painful then the piracy route. Usually the biggest hurdle to purchasing software is the price tag (but not always, some people just will never buy software and always pirate, but you can't do anything about that). And the biggest hurdle to piracy is some sort of DRM scheme, which is actually the second largest hurdle to purchasing software. Often times DRM only annoys the legitimate purchases, while the pirated version has all the DRM removed with less effort then you spend to put it in. Thanks to the wonder of electronic duplication, once the DRM is removed, then everyone can have a DRM free copy.
So you want a solution that only annoys illegitimate usage, but not legitimate purchases. This is much harder to do then expected.
Depending on the price tag for your software you might consider deploying it on a keyed USB drive (i.e. Dongle or USB stick with some special key). Then it is portable, but only on the hardware you provide. The user never has to worry about a secondary authentication scheme, and the DRM only becomes an issue when the hardware (which is harder to duplicate) is changed.
You say that it is only for a LAN environment, which doesn't necessarily mean that the computers will have internet access (and if they do, they probably have a proxy requirement) which means "phoning home" will be problematic. If you want the product to only be used on a specific LAN then you might require a license server to be installed on the LAN. Then the software could always check with the license server to make sure it is authorized. That won't work if you want it to run on multiple LAN's though.
Conversely if your price is low enough then most companies and people would rather buy the correct licenses and not risk the piracy. In actuality, depending on your clientele, most people will prefer legitimate licenses when they can, and DRM can actually discourage them from buying licenses.
Some alternatives:
Use a dongle, where the user of the software must plug in the dongle before your application can work.
At startup read a configuration file and if this is invalid or missing, halt the application or reduce its functionality. The configuration file should contain information about the user or company that licensed your software, and also a checksum to prevent users from changing the file. With such a file, serious companies are less likely to distribute this configuration files to others. Of course, you should then create one such configuration file per user that licenses your software.
Optionally, include specific computer information (type, memory, bios date, system guid, ...) that prevents the application from being run on other computers.
Make sure you make money from the service you can deliver, not only from the software you are selling. This service can include: providing upgrades, taking suggestions for improvements, assisting with problems, helping with domain-specific knowledge, ...
You can use some sort of license file and a "phone home" option that makes sure the same license is not used at more than one place concurrently.
If you have a large ordfer, you could try to get a memory stick with a special serial number and/or value in it that you can read out in the software (eg the exe must reside on a special memory stick)
Please note that a lot of users get quite annoyed by these things (we've used the first option)
Also please note that if commercially interesting, your app will be hacked. Make sure the effort someone has to take outweighs the profit the could make
One approach that also helps some is by custom branding. Each copy you sell would have compiled into it the name of the company it was sold too, which can be displayed as part of the splash screen as well as the about screen (along with a button to view the license terms). Most often this branding is done by using an external file which contains the information encrypted that when placed in the same directory as the executable is used to unlock the application as well as possibly provide additional functionality.
Unfortunately with todays software firewalls, most of the simple solutions to disallow running multiple copies on a network are not practical while still maintaining true portability, or requiring internet access to a server that you fully control.
Yes, piracy is a problem, but if you continue to offer great support and there is an additional "visible" benefit to purchasing, you can help offset this in your favor.
If you need trial protection, you can count uses/days if you have any sort of database where the user will have invested time and data, and won't want to lose it. Just encrypt the counter and place in the database somwhere. The user can then only reset the trial by wiping out the database. Depending on the type of app, this may be effective, or not.
Another approach is to not have a portable trial at all, but offer it as an incentive for purchase. i.e. conduct the trial on the desktop, and when they purchase a license, they get a license key that allows it to run on portable devices.
I recommend the PortableApps.Com framework for launching your app. It's free. You need to make your "launcher" open-source, but not your app itself. You can still run on a bare drive, if you follow their pattern.

Where does an application store "I'm deactivated" on Windows? [closed]

Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 7 years ago.
Improve this question
Applications often have registration keys.
It can arguably be placed in a file or in the registry.
Sometimes, an application is deactivated by entry of another key,
or the passing of a date, etc. Where can one safely
store such information about an application be deactivated?
A file isn't the answer; a backup copy can be restored to
defeat this. The registry is a weak answer, only because
most people don't know its there, and don't think to restore it,
and if they do they restore the whole thing which usually
has other discouraging side effects.
It seems to me that storing deactivation information is
hopelessly unsafe, as old copies can always be restored.
At best one can hide this data by obfuscation under
cryptically named files or registry keys.
Is there a standard trick I don't know, or a standard
scheme supported by Windows, that helps with this problem?
Round 2: I've seen a number of answers. None of them
specifically say "you can't do this" but several imply
that phoning home is the only good choice (for "deactivation").
Let's assume phoning home and dongles are NOT the answer,
and one has to leave something on the machine. What do
typical licensing schemes actually do in this case?
In contrast to the IPhone and other closed environments on an open platform like windows/linux you always run a very high risk that the protection is easily circumventable (local serial protection) or will be cracked by reversing and patching your code. Virtually every modern single player game has this problem. Additionally it is very hard to find a solution that does not annoy the user too much. We all remember the Sony-CD-Rootkit disaster and in the game industry its the always the newest DVD-protection that doesn't work on all drives the way its supposed to. But what can you do? You can try the usual serial, call-home option and ban certain serials in newer updates (Adobe, FlashFXP, Windows). If you have a very low consumer base, this probably is enough for you. If - for whatever reason - that is not an option, what about an USB-Dongle that is needed to use your software. Heard of quite some CAD-programs using this. One last thing you can look into, what about watermarking your application? If it shows up on certain p2p networks you will maybe be able to see where the leak is. Basically nothing will give you a 100% guarantee, but there are options to make it more difficult for the average user... Please keep in mind that most of your money should be spend on creating a great product not in buying mostly useless protection!
Create and sign a license file on a server. If you use public key cryptography, the license file can't be faked easily. Your application can be of course cracked to not need the license, but that's a different thing.
Here is a short but pretty good overview of different options.
http://www.developer-resource.com/how-to-protect-software.htm
Ya,you could encrypt things,that's what they do!.Check the net for various licensing schemes.Even microsoft has one...Microsoft Software Licensing and Protection
You can use the Microsoft Cryptographic API to develop you code.Plus obscure you assemblies or dlls.Force user activation.
All protection schemes are vulnerable to some type of attack. Encryption of information does help prevent attacks because the information is stored in an obfuscated way, but even this isn't unbreakable.
Another possible option is to store the actual activation state information remotely and leave a reference to this information on the machine, possibly encrypted. There are many ways to do this but one that comes to mind is to store a GUID of some kind that you could then look up in your database
One downfall of this is the requirement of an internet connection, I don't know if that is prohibitive or not but the general idea is to remove the activation state from a machine you don't control and put it on one that you do

How to make a shareware program with a free demo [closed]

Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 8 years ago.
Improve this question
I have a game that I'd like to sell with the following system: give away a demo (say, with the first few levels) and sell the full version. I'd like to make the transition to the full version as seamless as possible for the user. I've never sold anything before online, so I'm not sure how that would work (even if there were no free demo).
This seems like a very common issue, so I'd imagine there's a standard solution. I'm writing in C++, targeting Windows, and my installer is generated by NSIS.
There are two options:
A separate demo and full version. Your ecommerce provider will send the full version to people who buy it.
A demo that is unlocked by a registration key or online activation process. Registration keys can be generated on the fly (or taken from a pre-generated list). Ecommerce providers can then send the keys to customers immediately after purchase.
Both approaches have their pros and cons.
Separate full version
Smaller demo file, saves bandwidth
Less technical support required for customers who buy full version (in my experience)
Two builds of the game, more testing
Harder to distribute updated versions to customers - need to keep a login for each customer or a secret URL that expires after a few days.
Unlockable demo
Contains all assets, may waste bandwidth
Easier to distribute cracked version (pirates can distribute a 10KB patch or reg key and link to your demo file, more bandwidth waste)
Single build, less testing
Easy to distribute updated versions (everybody can download the same public version)
Regarding a "general" solution, look around for commercial DRM wrappers such as this one. Some game portals/publishers also require that you use their own wrapper.
Don't ship your full product as a demo that can be activated. This way you don't eliminate piracy (which will still be something you will have to deal with) but at least you remove the possibility of someone just downloading the demo, cracking it, and spreading it around (or even just a cracked executable). They would at least have to buy the full version first.
As for checking a legit customer is using the software, you can indeed do some online authentication as Danny suggest but note that this will only stop people from using your online services and it often is just a matter of time before a qualified cracker/reverser makes sure that your product's offline features can be used without purchase.
By not shipping the full product immediately, it does make upgrading a little harder, but there are ways around this, ex: Updater that only works after online authentication.
If you develop it correctly you should be able to have a checking mechanism after the Xth level. This checking mechanism could basically hit a registry key. This registry key could have some encoded information which was generated by your program. The key could basically represent an MD5 hash (or SHA-1 or SHA-2 if you really concerned with high security) of the installed machine MAC Address, the first and last name, so and so forth. When someone purchases the game, you have them input that data in a form and then generate a code to send along to the user to unlock the game. You could even take that same algorithm and put it on your ASP.NET website and automate the key generation after a purchase has been made.
My 2 cents:
Dont spend too much time devising methods against piracy. Use simple serial generator mechanism to unlock the game which user can enter manually during the execution.
I would say have a single build which can switch to trial mode or full based on the serial key entered. This will reduce the overhead of maintaining two separate code.
It is a personal opinion, that people who really buy software at first place will buy your game no matter how many pirated versions are available. So make registeration purpose as simple as possible which will deter a normal user from cracking it and at the same time easy to use. Hackers will crack it no matter what protection you use it. Otherwise we wont see the pirated copies of microsoft/adobe products etc who spend so much on making their products piracy free. No matter what they charge, people do buy it. Its the quality of the product which will encourage your users to buy your product.
Also, try not to impose locks on your software like using MAC address etc for generating the serial numbers etc. Online activation may be a good idea but remember people are skeptical as to what information you try to transmit while activation. Also you might have to provide an alternate mechanism for offline activation if your customers dont have internet connection or work in separate LAN.
Once you see that you game is getting popular and you see more pirated copies with users, you may invest more time and money on developing anti-piracy techniques.

Selling source code, What should I be aware of [closed]

Closed. This question is off-topic. It is not currently accepting answers.
Want to improve this question? Update the question so it's on-topic for Stack Overflow.
Closed 10 years ago.
Improve this question
I have received a request of buying the source code of a website I have developed and I wondered if anybody have been in the same situation and if there is anything I should specially be aware of. Anybody got some advise on how I should handle this situation?
First - a caveat - I'm not a lawer. Not at all. But I care alot about intellectual property and not getting sued, so I try to learn about it a bit.
In no particular order:
Double check your employment rules - when you took the job currently paying you money, what is your arrangment? Did you have to sign any statements giving your company control over all the code you produced? Even if it was a personal, unpaid project - corporate ownership can get you if you signed a strict intellectual property agreement.
Used open source? - there are a few main open source licenses, read through and check them to see the terms for sale of a product with dependancies on open source.
What deliverables does buyer expect? - Built code? source code? Also - what can you do to protect your code (obfuscation).
Do they expect support? - be careful, in my experience with corporate customers, a helpful, free of charge "sure, just call me if you have a quick question" can quickly become time consuming. If you are willing to throw in a free couple hours, be very clear that you will give up to X hours of support for free. And be clear about what your billing rate is after. If you really don't want to support it, make the cost of your time very high.
What sort of support do they want? - answers & configuration help? Bug fixes?
What sort of installation instructions are expected?
What do they own when they buy this? - a single installation for a single server? a site-wide license to install it wherever they wish? or --- worst case -- do they own this lock, stock and barrel such that you may no longer develop it and continue to use it yourself?
Get these answers cleared up, in writing, with signatures.
It's a good idea to have someone external read it to check for ambiguity.
It's an even better idea to draw up the agreement and have a lawyer read it - your lawyer, not the buyer's lawyer.
Avoid any nod/wink/handshake deals. Personal trust is great, but people change if the situation becomes stressful. Or people come and go within companies - the buyer today may be a different person tomorrow.
The first thing you need to consider is:
What license are you providing the code under?
If you don't stipulate a license, they're pretty much free to do with it what they want. Is that what you want? It's hard to answer the question without knowing the specifics of the situation: why are you selling the source code?
If this is a customer and so it's they can do their own custom modifications that you were otherwise being paid to do, the price should reflect that "lost work". Also, you will want to limit their ability to redistribute or resell that source code.
If someone just likes your site and wants the code, be very wary because there's every chance they'll just take it and set up their own. This may or may not be an issue for you. But again consider the issues of resale, redistribution, usage rights and ownership.
Depending on what the code is for, you may also want to consider what it is used for, what it can be used for and how that will affect you professionally or otherwise. It's possibly you may want to restrict the code from being used for certain things (eg adult or poker sites) or you want to require attribution.
Also for all of these things, you need to consider what terms transfer in the event of redistribution (ie how "viral" your license is).
There are lots of open source licenses out there (GPL, Apache, MIT, BSD, MPL, LGPL, etc). I'd suggest you take one as a basis and modify it to suit your tastes. You're far less likely to get in trouble that way than you are with coming up with your own terms.

Resources