Active12 months ago
How can I create a product key for my C# Application?
I need to create a product (or license) key that I update annually. Additionally I need to create one for trial versions.
Now, first 3 digit of serial no is xyz. 4 digit of serial no should be Item Type(e.g if Item type is 'b' then serial no should be xyzb). 5 digit of serial no should be like this: In a day, for first Item batch number of a Item type, 5th digit should be 1 and it will remain 1 for that day.For the next different Item batch number it should be 2 and it will remain 2 for that day. Same rule applied for next day and other item type. 18 Digit Product Key Serial Numbers. Convert 18 Digit Product Key trail version to full software. [Working] Windows XP Product Keys Free. When you buy a genuine Windows XP, you get a genuine Windows product key. These free product key for Windows XP will help to make sure that you are using genuine Windows. When you receive this 25 digit Windows XP product keys, you have to follow a process to activate the windows in your system. 18 Digit Product Key Serial Numbers. Convert 18 Digit Product Key trail version to full software.
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14 Answers
Serial key for iobit malware fighter. You can do something like create a record which contains the data you want to authenticate to the application. This could include anything you want - e.g. program features to enable, expiry date, name of the user (if you want to bind it to a user). Then encrypt that using some crypto algorithm with a fixed key or hash it. Then you just verify it within your program. One way to distribute the license file (on windows) is to provide it as a file which updates the registry (saves the user having to type it).
Beware of false sense of security though - sooner or later someone will simply patch your program to skip that check, and distribute the patched version. Or, they will work out a key that passes all checks and distribute that, or backdate the clock, etc. It doesn't matter how convoluted you make your scheme, anything you do for this will ultimately be security through obscurity and they will always be able to this. Even if they can't someone will, and will distribute the hacked version. Same applies even if you supply a dongle - if someone wants to, they can patch out the check for that too. Digitally signing your code won't help, they can remove that signature, or resign it.
You can complicate matters a bit by using techniques to prevent the program running in a debugger etc, but even this is not bullet proof. So you should just make it difficult enough that an honest user will not forget to pay. Also be very careful that your scheme does not become obtrusive to paying users - it's better to have some ripped off copies than for your paying customers not to be able to use what they have paid for.
Another option is to have an online check - just provide the user with a unique ID, and check online as to what capabilities that ID should have, and cache it for some period. All the same caveats apply though - people can get round anything like this.
Consider also the support costs of having to deal with users who have forgotten their key, etc.
edit: I just want to add, don't invest too much time in this or think that somehow your convoluted scheme will be different and uncrackable. It won't, and cannot be as long as people control the hardware and OS your program runs on. Developers have been trying to come up with ever more complex schemes for this, thinking that if they develop their own system for it then it will be known only to them and therefore 'more secure'. But it really is the programming equivalent of trying to build a perpetual motion machine. :-)
frankodwyerfrankodwyer11.8k88 gold badges4545 silver badges6969 bronze badges
Who do you trust?
I've always considered this area too critical to trust a third party to manage the runtime security of your application. Once that component is cracked for one application, it's cracked for all applications. It happened to Discreet in five minutes once they went with a third-party license solution for 3ds Max years ago.. Good times!
Seriously, consider rolling your own for having complete control over your algorithm. If you do, consider using components in your key along the lines of:
- License Name - the name of client (if any) you're licensing. Useful for managing company deployments - make them feel special to have a 'personalised' name in the license information you supply them.
- Date of license expiry
- Number of users to run under the same license. This assumes you have a way of tracking running instances across a site, in a server-ish way
- Feature codes - to let you use the same licensing system across multiple features, and across multiple products. Of course if it's cracked for one product it's cracked for all.
Then checksum the hell out of them and add whatever (reversable) encryption you want to it to make it harder to crack.
To make a trial license key, simply have set values for the above values that translate as 'trial mode'.
And since this is now probably the most important code in your application/company, on top of/instead of obfuscation consider putting the decrypt routines in a native DLL file and simply P/Invoke to it.
Several companies I've worked for have adopted generalised approaches for this with great success. Or maybe the products weren't worth cracking ;)
Peter Mortensen14.4k1919 gold badges8888 silver badges117117 bronze badges
SpiffeahSpiffeah
If you are asking about the keys that you can type in, like Windows product keys, then they are based on some checks. If you are talking about the keys that you have to copy paste, then they are based on a digitial signature (private key encryption).
A simple product key logic could be to start with saying that the product key consists of four 5-digit groups, like
abcde-fghij-kljmo-pqrst
, and then go on to specify internal relationships like f+k+p should equal a, meaning the first digits of the 2, 3 and 4 group should total to a. This means that 8xxxx-2xxxx-4xxxx-2xxxx is valid, so is 8xxxx-1xxxx-0xxxx-7xxxx. Of course, there would be other relationships as well, including complex relations like, if the second digit of the first group is odd, then the last digit of the last group should be odd too. This way there would be generators for product keys and verification of product keys would simply check if it matches all the rules.Encryption are normally the string of information about the license encrypted using a private key ( digitally signed) and converted to Base64. The public key is distributed with the application. When the Base64 string arrives, it is verified (decrypted) by the public key and if found valid, the product is activated.
Peter Mortensen14.4k1919 gold badges8888 silver badges117117 bronze badges
Create An 18 Digit Serial Key
Kinjal DixitKinjal Dixit6,09422 gold badges4343 silver badges6363 bronze badges
Whether it's trivial or hard to crack, I'm not sure that it really makes much of a difference.
The likelihood of your app being cracked is far more proportional to its usefulness rather than the strength of the product key handling.
Personally, I think there are two classes of user. Those who pay. Those who don't. The ones that do will likely do so with even the most trivial protection. Those who don't will wait for a crack or look elsewhere. Either way, it won't get you any more money.
spenderspender90.5k2323 gold badges171171 silver badges291291 bronze badges
I have to admit I'd do something rather insane.
- Find a CPU bottleneck and extract it to a P/Invokeable DLL file.
- As a post build action, encrypt part of the DLL file with an XORencryption key.
- Select a public/private key scheme, include public key in the DLL file
- Arrange so that decrypting the product key and XORing the twohalves together results in the encryption key for the DLL.
- In the DLL's DllMain code, disable protection (PAGE_EXECUTE_READWRITE)and decrypt it with the key.
- Make a LicenseCheck() method that makes a sanity check of thelicense key and parameters, then checksums entire DLL file, throwinglicense violation on either. Oh, and do some other initializationhere.
When they find and remove the LicenseCheck, what fun will followwhen the DLL starts segmentation faulting.
Create An 18 Digit Serial Key Generator
Peter Mortensen14.4k1919 gold badges8888 silver badges117117 bronze badges
JoshuaJoshua26k55 gold badges5050 silver badges108108 bronze badges
There is the option Microsoft Software Licensing and Protection (SLP) Services as well. After reading about it I really wish I could use it.
I really like the idea of blocking parts of code based on the license. Hot stuff, and the most secure for .NET. Interesting read even if you don't use it!
Microsoft® Software Licensing and Protection (SLP) Services is a software activation service that enables independent software vendors (ISVs) to adopt flexible licensing terms for their customers. Microsoft SLP Services employs a unique protection method that helps safeguard your application and licensing information allowing you to get to market faster while increasing customer compliance.
Note: This is the only way I would release a product with sensitive code (such as a valuable algorithm).
Peter Mortensen14.4k1919 gold badges8888 silver badges117117 bronze badges
ccookccook3,96555 gold badges4747 silver badges7979 bronze badges
If you want a simple solution just to create and verify serial numbers, try Ellipter. It uses elliptic curves cryptography and has an 'Expiration Date' feature so you can create trial verisons or time-limited registration keys.
Peter Mortensen14.4k1919 gold badges8888 silver badges117117 bronze badges
RolandRoland
Another good inexpensive tool for product keys and activations is a product called InstallKey. Take a look at www.lomacons.com
CheChe
One simple method is using a Globally Unique Identifier (GUID). GUIDs are usually stored as 128-bit values and are commonly displayed as 32 hexadecimal digits with groups separated by hyphens, such as
{21EC2020-3AEA-4069-A2DD-08002B30309D}
.Use the following code in C# by
System.Guid.NewGuid()
.I hope it helps.
Peter Mortensen14.4k1919 gold badges8888 silver badges117117 bronze badges
Aishwar C NigamAishwar C Nigam
The trick is to have an algorithm that only you know (such that it could be decoded at the other end).
There are simple things like, 'Pick a prime number and add a magic number to it'
More convoluted options such as using asymmetric encryption of a set of binary data (that could include a unique identifier, version numbers, etc) and distribute the encrypted data as the key.
Might also be worth reading the responses to this question as well
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Rowland ShawRowland Shaw33.2k1212 gold badges8484 silver badges153153 bronze badges
There are some tools and API's available for it. However, I do not think you'll find one for free ;)
There is for instance the OLicense suite:http://www.olicense.de/index.php?lang=en
Frederik GheyselsFrederik Gheysels49.8k88 gold badges8686 silver badges143143 bronze badges
You can check LicenseSpot. It provides:
- Free Licensing Component
- Online Activation
- API to integrate your app and online store
- Serial number generation
- Revoke licenses
- Subscription Management
JoseJose
I'm going to piggyback a bit on @frankodwyer's great answer and dig a little deeper into online-based licensing. I'm the founder of Keygen, a licensing REST API built for developers.
Since you mentioned wanting 2 'types' of licenses for your application, i.e. a 'full version' and a 'trial version', we can simplify that and use a feature license model where you license specific features of your application (in this case, there's a 'full' feature-set and a 'trial' feature-set).
To start off, we could create 2 license types (called policies in Keygen) and whenever a user registers an account you can generate a 'trial' license for them to start out (the 'trial' license implements our 'trial' feature policy), which you can use to do various checks within the app e.g. can user use Trial-Feature-A and Trial-Feature-B.
And building on that, whenever a user purchases your app (whether you're using PayPal, Stripe, etc.), you can generate a license implementing the 'full' feature policy and associate it with the user's account. Now within your app you can check if the user has a 'full' license that can do Pro-Feature-X and Pro-Feature-Y (by doing something like
user.HasLicenseFor(FEATURE_POLICY_ID)
).I mentioned allowing your users to create user accounts—what do I mean by that? I've gone into this in detail in a couple other answers, but a quick rundown as to why I think this is a superior way to authenticate and identify your users:
- User accounts let you associate multiple licenses and multiple machines to a single user, giving you insight into your customer's behavior and to prompt them for 'in-app purchases' i.e. purchasing your 'full' version (kind of like mobile apps).
- We shouldn't require our customers to input long license keys, which are both tedious to input and hard to keep track of i.e. they get lost easily. (Try searching 'lost license key' on Twitter!)
- Customers are accustomed to using an email/password; I think we should do what people are used to doing so that we can provide a good user experience (UX).
Of course, if you don't want to handle user accounts and you want your users to input license keys, that's completely fine (and Keygen supports doing that as well). I'm just offering another way to go about handling that aspect of licensing and hopefully provide a nice UX for your customers.
Finally since you also mentioned that you want to update these licenses annually, you can set a duration on your policies so that 'full' licenses will expire after a year and 'trial' licenses last say 2 weeks, requiring that your users purchase a new license after expiration.
I could dig in more, getting into associating machines with users and things like that, but I thought I'd try to keep this answer short and focus on simply licensing features to your users.
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ezekgezekg
Please check this answer: https://stackoverflow.com/a/38598174/1275924
The idea is to use Cryptolens as the license server. Here's a step-by-step example (in C# and VB.NET). I've also attached a code snippet for key verification below (in C#):
ArtemArtem
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Redeem your Student and Teacher edition purchase, convert a redemption code to a serial number, and more.
Depending on how you purchased your Adobe Student & Teacher edition product, you may have received a serial number or a redemption code.
You’ll need the serial number to register your product, update your product, upgrade to a Creative Cloud plan, or qualify for certain types of service plans. Use the redemption code—sent in less secure situations—to redeem your product license and get your serial number.
No serial number is needed for subscription or membership products. Simply sign in with your Adobe ID to activate your membership.
If you purchased a stand-alone version of a product—via a card, as a download, or on discs in a box (for example, Acrobat XI, Photoshop Elements, or Lightroom 6)—you will need your serial number to install the app. Enter your serial number when prompted during the installation of your app.
If you registered your product or downloaded it from Adobe.com, finding your serial number is simple. Adobe keeps track of it for you. Driver booster 6 rc key.
- To see a list of your registered products and their serial numbers, sign in with your Adobe ID and password.Note:Having trouble with your Adobe ID? See Adobe ID, sign-in, and account help.
- Click the Planstab, and then click My products in the left pane. A list of your registered products and serial numbers is displayed.
Serial number not showing up in your Adobe account?
Check the following table to find your serial number.How did you receive your product?Find your serial number:In a product box.Printed on the disc or disc sleeve.Note: For Elements products, the serial number is located on the Windows DVD sleeve.As a download from Adobe.In an email from Adobe containing the serial number for the product you purchased. Look for the subject line 'Your Serial Number' or 'Your Serial Numbers.'
Redeem products purchased from a store or online retailer
No serial number is needed for membership or subscription products such as Creative Cloud - Student and Teacher plan. Simply sign in with your Adobe ID to activate your membership.
If you purchased a membership from a retailer, however, you may have received a redemption code—for example, beneath the scratch-off foil on the back of a prepaid card. If you have a redemption code, follow the steps below to redeem your code and activate your membership.
Redeem a redemption code to activate your membership.
- Go to creative.adobe.com/educard and do one of the following:
- Have an Adobe ID? Enter it and your Adobe password, and click Sign In.
- Don't have an Adobe ID? Click Sign Up and follow the onscreen instructions.
- Enter the required information regarding your academic status and click Continue.
- Enter the 24-digit alphanumeric redemption code and click Activate Membership.Note:Redemption codes contain both letters and numbers. The other numeric codes such as the UPC code on your insert, card, or email are not your redemption code.
- Read the renewal plan terms and click Accept Terms & Conditions.
- If prompted, enter billing information and click Continue.
- In the window that appears, click Get Started again.
- You now have access to the apps that are included in your membership plan. Click Open the Creative Cloud app to start downloading your software.
18 Digit Card Number
If you purchased a stand-alone version of a product (for example, Acrobat XI, Photoshop Elements, or Lightroom 6), you need a serial number to activate your app. In the following table, choose the option that applies to you to find information about your serial number or redemption code.
What do you have? | Submit your product code and proof of eligibility to Adobe: | Find your redemption code or serial number: | Convert your redemption code to a serial number: |
A prepaid card Find your 19-digit numeric product code beneath the scratch-off foil on the back of the card. | Depending on your region, go to one of the following sites to submit your verification request or find out how to do so: North America: www.adobe.com/go/edu-validate Outside North America, one of the following: Europe, Middle East, Africa | Germany | France | Spain | Italy | Netherlands | Czech Republic | Poland | Asia/Pacific | Korea Verification can take 2–30 days. | Once your verification request has been approved: If you’re in North America: You receive an email with a 24-digit alphanumeric redemption code and a link to www.adobe.com/go/getserial to get your serial number. If you’re outside North America: You receive an email with a link back to your customer support case. The case contains your 24-digit alphanumeric redemption code and a link to www.adobe.com/go/getserial to redeem your redemption code. | 1. Go to www.adobe.com/go/getserial and sign in with your Adobe ID and password. If you don’t have an Adobe ID, click Create an Adobe ID and follow the onscreen instructions. 2. Enter the 24-digit alphanumeric redemption code you received in the email and click Redeem. 3. Depending on your product, a serial number appears, a download link appears, or both. 4. Make note of your serial number and click Download to begin installing your product. Make sure you retain the serial number in case you ever need to update your product or receive product support. Consider registering your Adobe product, which securely stores your serial number in your Adobe account. |
A product box Find your 22-digit alphanumeric product code on the disc sleeve, on an insert card, or on the product box. | Follow the instructions on the insert inside your product box. Depending on your region, go to one of the following sites to submit your verification request or find out how to do so: North America: www.adobe.com/go/edu-validate Outside North America, one of the following: Europe, Middle East, Africa | Germany | France | Spain | Italy | Netherlands | Czech Republic | Poland | Asia/Pacific | Korea Verification can take 2–30 days. | Once your verification request has been approved, you receive an email with a 24-digit numeric serial number. Make note of your serial number and enter your serial number when prompted during installation of your product. Make sure that you retain the serial number in case you ever need to update your product or receive product support. Consider registering your Adobe product, which securely stores your serial number in your Adobe account. | Not applicable. |
An email from the reseller Find your 19-digit numeric product code in an email from the reseller from which you purchased your product. | Follow the instructions in the email. Depending on your region, go to one of the following sites to submit your verification request or find out how to do so: North America: www.adobe.com/go/edu-validate Outside North America, one of the following: Europe, Middle East, Africa | Germany | France | Spain | Italy | Netherlands | Czech Republic | Poland | Asia/Pacific | Korea Verification can take 2–30 days. | Once your verification request has been approved, you receive an email with a 24-digit numeric serial number. Make note of your serial number and enter your serial number when prompted during installation of your product. Make sure that you retain the serial number in case you ever need to update your product or receive product support. Consider registering your Adobe product, which securely stores your serial number in your Adobe account. | Not applicable. |
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