ThinkSharp.Licensing

Introduction

ThinkSharp.Licensing is a simple library with fluent API for creating and verifying signed licenses. It provides the following functionallities:

• Creation / verification of hardware identifiers (Windows only)
• Creation / verification of serial numbers
• Creation / verification of signed licenses

Installation

ThinkSharp.Licensing can be installed via Nuget

 Install-Package ThinkSharp.Licensing 

API Reference

Singed License

The class SignedLicense encapsulates some license related information and a signature for verifying it. The license can be serialized / deserialized for storing it on the client. It has following public properties:

• IssueDate: date of the issuing (when the license was created)
• ExpirationDate: date of the expiration (may be DateTime.MaxValue for licenses without expiration)
• SerialNumber Optional: a serial number (See class SerialNumber below)
• PropertiesIDictionary<string, string> with custom key value pairs

The static Lic class is the entry point for the fluent API that allows to work with signed licenses. It has the following static properties:

• Lic.Builder: Object for creating signed license objects
• Lic.Verifyer: Object for verifiying serialized signed licenses and deserialize it.
• Lic.KeyGenerator: Object for creating private/public key pairs to use for signing

Usage

Create signed licenses

SignedLicenselicense=Lic.Builder.WithRsaPrivateKey(pk)// .WithSigner(ISigner).WithHardwareIdentifier(HardwareIdentifier.ForCurrentComputer())// .WithoutHardwareIdentifier().WithSerialNumber(SerialNumber.Create("ABC"))// .WithoutSerialNumber().WithoutExpiration()// .ExpiresIn(TimeSpan), .ExpiresOn(DateTime).WithProperty("Name","Bill Gates").WithProperty("Company","Microsoft")//... other key value pairs.SignAndCreate();

Serialize License

The SignedLicense can be serialized as encrypted base64 encoded string (default):

varencryptedText=license.Serialize();// FW9JbxVRYW8hcWBVZ3VHbGosEBxfYhlMZmshHHUxGBVbHBksc3// 9EHywLc2NNaWIsE39YaAxFbXo7BhhSYxwhZmBJYSAGGxkuEhUj// GREwFw08GxsxEBc8GywLER8jGBAuGRQ1EgEzExc5Ehs0GSAGZU// BsRRdOQk1tAGptX0RyLSdPRExxQUN1EWxoQ19jWE5nVCAGahJm// Ek8/GhFwSwY7ehk3Sm4+cRk4EFh4GVkydFh0U0NURAZUWBVnbW// 9eXQ5JTWtgElI4cHxaBFtEQ2ZBGlFiSmR5bWsuEHRfAENAYx8+// U09vQmM+Tg5SakFmcmxKFWM9YQ4yR2NVSVdidUwnE1BuS0BLeX// tbU0tifnNDQ25teVZjcXl2H2pQVnk7QEBTC19FXFRGeGs6T1FX// SUR0YmprFmknHRA5VBpOeUdYHQ==

or as plain text string:

varplainText=license.SerializePlainText();// 5BED5GAB-E5TGXKGK-01SI8MFF-7T099W78-SRH4// SNABC-3RTC-DMW7-9SC1-MAHA// 08/28/2017 00:00:00// 12/31/9999 23:59:59// Name:Bill Gates// Company:Microsoft// A3g2b310qk+7Q86jC2Z890ut2x3TuxxbUd+Xs4fMBRv/HmFl9s// 9PQV/zEcKM1pcjIuFJ/0YS+bAC22xnnbN2e/SJljYMK5N1J/3g// NYbvcUa+8qokmGRZZsfnURBcCaRwbQTz4KQvT7kaR+rIwuGXF6// dpViixIKj6D+618t7BRfY=

Verify License

For deserializing the license, the Lic.Verifier has to be used. If the license can not be deserialized hor has no valid signature, an exception is thrown.

SignedLicenselicense=Lic.Verifier.WithRsaPublicKey(publicKey)// .WithSigner(ISigner).WithApplicationCode("ABC")// .WithoutApplicationCode.LoadAndVerify(licenseText);

Create public/private key Pair

A public and private key pair can be generated using the Lic.KeyGenerator object:

SigningKeyPairpair=Lic.KeyGenerator.GenerateRsaKeyPair();Console.WriteLine(pair.PrivateKey);Console.WriteLine(pair.PublicKey);

Hardware Identifier

The hardware identifier is an identifier that derives from 4 characteristics of the computer's hardware (processor ID, serial number of BIOS and so on). The identifier may look like:

5BED5GAB-E5TGXKGK-01SI8MFF-7T099W78-SRH4

Each characteristic is encoded in one of first 4 parts (8 charachters). The hardware identifier will be accepted if at least 2 of the 4 characteristics are equal. That ensures, that the license doesn't become invalid if e.g. the processor of the computer changed. The last part (4 characters) is a check sum that can be used to detect errors in the the hardware identifier.

Usage

// Create:stringhardwareIdentifier=HardwareIdentifier.ForCurrentComputer();// Validate Checksumif(!HardwareIdentifier.IsCheckSumValid(hardwareIdentifier)){Console.WriteLine("Entered hardware identifier has errors.");}// Validate for current computerif(!HardwareIdentifier.IsValidForCurrentComputer(hardwareIdentifier)){Console.WriteLine("Entered license is not valid for this computer.");}

Serial Number

A serial number is an identifier with an alpha-numeric application code (3 character), some random characters and a check sum. It looks like SNXXX-YYYY-YYYY-YYYY-ZZZ where XXX is the application code, YYYY is the random part and ZZZ is the check sum. E.g.:

SNABC-D156-KYJF-C4M5-1H96 

Usage

// ABC = application codestringserialNumber=SerialNumber.Create("ABC");// Validate CheckSumif(!SerialNumber.IsCheckSumValid(serialNumber)){Console.WriteLine("Entered serial number is not valid.");}

License

ThinkSharp.Licensing is released under The MIT license (MIT)

Versioning

We use SemVer for versioning. For the versions available, see the tags on this repository.

Credits

Thanks to Peter-B- for simplifying the project structure and improving compatibility to .Net 5.0.

Donation

If you like ThinkSharp.Licensing and use it in your project(s), feel free to give me a cup of coffee :)