• Serial Key Crack
• Help Me Create A Username
• Create A Username And Password
• Serial Key Finder
• Create Serial Key From Username Password

This value is specific to AWS CloudFormation and can only be incremented.Incrementing this value notifies AWS CloudFormation that you want to rotate your access key. Connect to ESET web based services and products with your ESET Account. License Key Enter the license key (all symbols, including hyphens) that you received with the purchase of your ESET product.

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.

Related:

J3r3myKJ3r3myK

14 Answers

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. :-)

frankodwyerfrankodwyer

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 Mortensen

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 MortensenKinjal DixitKinjal Dixit

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.

Additional Information: Record of Gambling in HD. Export recordings to popular formats and devices! Recording web video in real time. Benchmark games. Upload to YouTube ™ or Facebook Record audio comments Capture screenshots Play in HD – record to SD.

spenderspender

I have to admit I'd do something rather insane.

1. Find a CPU bottleneck and extract it to a P/Invokeable DLL file.
2. As a post build action, encrypt part of the DLL file with an XORencryption key.
3. Select a public/private key scheme, include public key in the DLL file
4. Arrange so that decrypting the product key and XORing the twohalves together results in the encryption key for the DLL.
5. In the DLL's DllMain code, disable protection (PAGE_EXECUTE_READWRITE)and decrypt it with the key.
6. 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.

Peter MortensenJoshuaJoshua

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 Mortensenccookccook

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 Mortensen

Another good inexpensive tool for product keys and activations is a product called InstallKey. Take a look at www.lomacons.com

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().

Serial Key Crack

I hope it helps.

Peter Mortensen

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

Rowland ShawRowland Shaw

Help Me Create A Username

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 Gheysels

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

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:

1. 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).
2. 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!)
3. 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.

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#):

Not the answer you're looking for? Browse other questions tagged c#.netlicense-key or ask your own question.

-->

Create A Username And Password

APPLIES TO: SQL Server Azure SQL Database Azure SQL Data Warehouse Parallel Data Warehouse

Creates a database master key.

Syntax

Arguments

PASSWORD ='password'
Is the password that is used to encrypt the master key in the database. password must meet the Windows password policy requirements of the computer that is running the instance of SQL Server. password is optional in SQL Database and SQL Data Warehouse.

Remarks

The database master key is a symmetric key used to protect the private keys of certificates and asymmetric keys that are present in the database. When it is created, the master key is encrypted by using the AES_256 algorithm and a user-supplied password. In SQL Server 2008 and SQL Server 2008 R2, the Triple DES algorithm is used. To enable the automatic decryption of the master key, a copy of the key is encrypted by using the service master key and stored in both the database and in master. Typically, the copy stored in master is silently updated whenever the master key is changed. This default can be changed by using the DROP ENCRYPTION BY SERVICE MASTER KEY option of ALTER MASTER KEY. A master key that is not encrypted by the service master key must be opened by using the OPEN MASTER KEY statement and a password.

The is_master_key_encrypted_by_server column of the sys.databases catalog view in master indicates whether the database master key is encrypted by the service master key.

Information about the database master key is visible in the sys.symmetric_keys catalog view.

For SQL Server and Parallel Data Warehouse, the Master Key is typically protected by the Service Master Key and at least one password. In case of the database being physically moved to a different server (log shipping, restoring backup, etc.), the database will contain a copy of the master Key encrypted by the original server Service Master Key (unless this encryption was explicitly removed using ALTER MASTER KEY DDL), and a copy of it encrypted by each password specified during either CREATE MASTER KEY or subsequent ALTER MASTER KEY DDL operations. In order to recover the Master Key, and all the data encrypted using the Master Key as the root in the key hierarchy after the database has been moved, the user will have either use OPEN MASTER KEY statement using one of the password used to protect the Master Key, restore a backup of the Master Key, or restore a backup of the original Service Master Key on the new server.

For SQL Database and SQL Data Warehouse, the password protection is not considered to be a safety mechanism to prevent a data loss scenario in situations where the database may be moved from one server to another, as the Service Master Key protection on the Master Key is managed by Microsoft Azure platform. Therefore, the Master Key password is optional in SQL Database and SQL Data Warehouse.

Important

You should back up the master key by using BACKUP MASTER KEY and store the backup in a secure, off-site location.

The service master key and database master keys are protected by using the AES-256 algorithm.

Permissions

Requires CONTROL permission on the database.

Examples

The following example creates a database master key for the current database. The key is encrypted using the password 23987hxJ#KL95234nl0zBe.

Serial Key Finder

See Also

Create Serial Key From Username Password

sys.symmetric_keys (Transact-SQL)
sys.databases (Transact-SQL)
OPEN MASTER KEY (Transact-SQL)
ALTER MASTER KEY (Transact-SQL)
DROP MASTER KEY (Transact-SQL)
CLOSE MASTER KEY (Transact-SQL)
Encryption Hierarchy